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May-Lissa Faustin
Big Idea Two: Biological systems utilize free energy and molecular bindings
to grow, to reproduce, and to maintain dynamic homeostasis.
Living systems require free energy and matter to maintain order, grow, and
reproduce. Organisms use many strategies to capture, use, and store
energy and other important resources.
There are autotrophs and heterotrophs. Autotrophs synthesize their foods
from inorganic substances using chemical energy or solar energy. While
heterotrophs on the other side, synthesize their foods from organic
substances. They use organic carbon for growth, while autotrophs are
different.
There are different types of autotrophs and heterotrophs. There are photo
autotrophs which require sunlight energy, fixes CO2 into organic
compounds. There are chemo autotrophs which require energy from
inorganic compounds, and fixes CO2 into organic compounds.
Photoheterotrophs require sunlight energy, and organic compounds from
other organisms. Chemohetertrophs, require energy from inorganic
compounds, and organic compounds from other organisms.
Autotrophic cells get free energy by the process of photosynthesis and
chemosynthesis. Photosynthesis, are processes used by plants and other
autotrophic organisms to convert light energy from the sun into chemical
energy that can be used for those organisms activities.
Important structures that are involved in photosynthesis are, the stomata,
stroma, chloroplasts, chlorophyll, and the thylakoids. The thylakoid
membrane is concerned with the initial conversion of light energy into
chemical energy that's stored in ATP and NADH. The stroma on the other
hand, takes place in the substance surrounding the thylakoids.
Chloroplasts take in sunlight and convert it into energy. The chloroplasts
contain chlorophyll which gives the plants the green color that plants
usually have.
In photosynthesis, Organisms split water as a source of electrons, and then
they release O2. Electrons also reduce CO2 to sugars.
There are two stages of photosynthesis, which are the light reactions, and
the Calvin cycle. In the light reactions, the light that's absorbed creates
NADPH, water splits, ATP is produced, phosphorylation occurs, and the
Thylakoids are involved. Phosphorylation is, the addition of a phosphate
group to an organic molecule, or protein. It can either activate or deactivate
an enzyme. In the Calvin Cycle on the other hand, there's carbon fixation, it
uses NADPH and ATP, lastly. The stroma is involved.
There are three different types of variables that affect the rate of
photosynthesis. Those are environmental variables, plant or leaf variables,
and method variables. Environmental variables include light intensity, light
color, temperature, and the pH of the solution. The plant or leaf variables
that affect the rate of photosynthesis are the leaf color, the leaf size, leaves
kept in bright light, the type of plant, and leaf age. The method variables
that affect the rate of photosynthesis are the sizes of the leaf disk, the leaf
disk overlap, and the soap amount.
Chemosynthesis captures the energy that's present in inorganic molecules.
These things include cellular respiration and fermentation, which harvests
free energy from sugars to produce free energy carriers, including ATP.
The free energy that's available in the sugars drives metabolic pathways
into the cells.
In Cellular Respiration, there are three separate steps that happen. These
steps are glycolysis, the Krebbs cycle, and oxidative phosphorylation.
In glycolysis, the six carbon sugar glucose is broken down into two
molecules of a three carbon molecule which is called pyruvate. That
change is accompanied by a net gain of 2ATP molecules and 2NADH
molecules. Fact! Glycolysis occurs in the cytosol.
The Krebbs cycle on the other hand occurs in the mitochondria, and
generates a pool of chemical energy which is ATP, NADH, and FADH2,
from the oxidation of pyruvate, and the end product of glycolysis. Pyruvate
is transported into the mitochondria and loses carbon dioxide so that it can
form acetyl-CoA which is a two carbon molecule. When acetyl-CoA is
oxidized to Carbon Dioxide in the Krebbs cycle, chemical energy is
released and captured in the form of ATP, NADH, and FADH2.
In Oxidative phosphorylation, the electron transport chain allows the
release of large amounts of chemical energy stored in reduced NADH+,
and reduced FADH2. The energy is then released into the captured form of
ATP. The electron transport chain consists of a series of molecules, mostly
proteins, embedded in the inner mitochondrial membrane.
In fermentation, all cells are able to synthesize ATP via the process of
glycolysis. In many cells, if oxygen isn't present pyruvate is metabolized,
which is what's called fermentation.
Fermentation compliments glycolysis and makes it possible for ATP to be
continually produced in the absence of oxygen. By oxidizing the NADH
that's produced in glycolysis, fermentation regenerates NAD+, which can
take a part in glycolysis again, to produce more ATP.
The chemical energy that's stored in glucose generates more ATP in
aerobic respiration than in respiration without oxygen. Each of the
molecules of glucose can generate 36-38 molecules of ATP in aerobic
respiration but only 2ATP molecules in respiration without oxygen.
OPEN RESPONSE TIME!:
#1:
Cells transport substances across their membranes. Choose THREE of
the following four types of cellular transport.
Osmosis
Active transport
Facilitated diffusion
Endocytosis/ Exocytosis
For each of the three types of transport you choose,
a. describe the transport process and explain how the organization of cell
membranes functions in the movement of specific molecules across
membranes, and
b. explain the significance of each type of transport to a specific cell (you
may use different cell types as examples)
#8 (1993) (also photo and resp)
Membranes are important structural features of cells.
a. Describe how membrane structure is related to the transport of
materials across a membrane.
b. Describe the roles of membranes in the synthesis of ATP in either
cellular respiration or photosynthesis.
#12
Photosynthesis and cellular respiration recycle oxygen in ecosystems.
Respond to TWO (and only two) of the following:
a. Explain how the metabolic processes of cellular respiration and
photosynthesis recycle oxygen.
b. Discuss the structural adaptations that function in oxygen
exchange between each of the following organisms and its environment : a
plant, an insect, a fish.
c. Trace a molecule of O2 from the environment to a muscle cell in a
vertebrate of your choice.
#13 (1995)
Energy transfer occurs in all cellular activities. For 3 of the following 5
processes involving energy transfer, explain how each functions in the cell
and give an example. Explain how ATP is involved in each example you
choose.
-
cellular movement
active transport
synthesis of molecules
chemiosmosis
fermentation
#14
The rate of photosynthesis may vary with change that occur in
environmental temperature, wavelength of light, and light intensity. Using a
photosynthetic organism of your choice, choose only ONE of the three
variables (temperature, wavelength, , or light intensity) and for this variable
- design a scientific experiment to determine the effect of the
variable on the rate of photosynthesis for the organism
- explain how you would measure the rate of photosynthesis in your
experiment
- Describe the results you would expect. Explain why you would
expect these results.
#15
Energy is neither created nor destroyed, but it is changed from one form to
another. Energy transfer is an important concept in cellular biology. In
most eukaryotic cells, chemical bond energy in glucose is eventually
converted to the chemical bond energy in ATP molecules in the process of
aerobic cellular respiration.
a. The majority of ATP molecules are produced in the process of
oxidative phosphorylation. Describe this process including the names and
locations of the structures involved and the formation of the electrochemical
gradient.
b. For 3 of the following situations, discuss the role of ATP in
completing these examples of cellular work.
- active transport
-Glucose production in the dark reaction
- Cytokinesis in an animal cell
- Movement of a flagellum
- Contraction of a muscle
- Control of the stages in mitosis
In case you didn’t know
what any of the questions
up there were asking?
What is Osmosis?:
Osmosis is the process
where fluids pass through a
semi permeable
membrane, moving from an
area where solute (such as
salt) is present in areas of
low concentration, to an area where solute is present in areas of high
concentration. The end result of this would be that there will be equal
amounts of fluid on either side of the barrier, creating an isotonic. (Isotonic
is, of equal tension. What’s on the inside would be equal to what’s on the
outside).
Key terms associated with osmosis are as follows:
Solvent this is the fluid that passes through the membrane.
Then there is solute which is, the dissolved substance in the fluid.
Together the solvent and the solute make up a solution.
Fact:
When the solution has low levels of a solute, it’s considered to be
hypotonic. While solutions with high solute levels are known as hypertonic.
Plants use osmosis to absorb water and nutrients from the soil. The
solutions in the roots are hypertonic, drawing in water from the soil. Roots
are like selective permeable membranes, taking in not only water, but
useful solutes, such as minerals, that the plant will need for survival.
Osmosis plays a critical role in plants in animals with fluids coming in and
out of the cell wall to bring in nutrients and carry out waste.
The fluid passes both in and out of the selective permeable membrane in
osmosis, but usually there’s a net flow in one direction or the other,
depending on which side of the membrane has the higher concentration of
solutes.
What is selectively permeable?:
Selective permeability is the property of a living cell membrane that allows
the cell to control which molecules can pass through the membrane,
moving into or out of the cell.
What is active transport?:
Active transport is the pumping of solutes across a biological membrane
against their concentration. The ability of cells to be able to maintain small
solutes with the cytoplasm, within the cytoplasm at concentrations higher
than the surrounding fluid of the cell is essential when it comes to cell
survival.
To really understand active transport, you have to understand passive
transport, which is the transport of a substance across a cell membrane by
diffusion; energy is not required. Active transport on the other hand, does
require energy. You also have to understand the second law of
Thermodynamics, which states that, the entropy of an isolated system
never decreases.
Passive transport is the natural movement of solutes across a membrane,
down the concentration gradient.
An example of this type of active transport protein is the sodium-potassium
pump. Most animal cells hold a higher concentration of potassium, and a
lower concentration of sodium, than what is found in the extracellular
environment. Since sodium ions carry a positive charge and potassium ions
carry a negative charge, this imbalance represents not only a concentration
gradient, but also an electrochemical gradient. Sodium-potassium pumps
move three sodium ions out of the cell for every two potassium ions they
bring into it, resulting in a net negative charge on the cell as a whole. The
difference of charges on each side of the cellular membrane creates a
voltage — the membrane potential — that allows the cell to act as a
battery, and power cellular work. <http://www.wisegeek.com/what-is-activetransport.htm>
What is facilitated diffusion?:
Facilitated diffusion is a type of passive transport that allows substances to
cross membranes with the assistance of special transport proteins.
What is endocytosis, and exocytosis? What’s the difference?:
Endocytosis is the taking in of matter by a living cell by invagination of its
membrane to form a vacuole.
While exocytosis is the process by which the contents of a cell vacuole are
released to the exterior through fusion of the vacuole membrane with the
cell.
Through exocytosis, the membrane used to form a vesicle is restored to the
surface of the cell.
What is chemiosmosis?:
Chemiosmosis is, the diffusion of ions across a selectively permeable
membrane.
Labs:
Plant Pigments and Photosynthesis
by Theresa Knapp Holtzclaw
Introduction
In photosynthesis, plant cells convert light energy into chemical energy that
is stored in sugars and other organic compounds. Critical to the process
is chlorophyll, the primary photosynthetic pigment in chloroplasts.
This laboratory has two separate activities: I. Plant Pigment
Chromatography, and II. Measuring the Rate of Photosynthesis. Select the
one you want to study, beginning with Key Concepts for that section.
Key Concepts I: Plant Pigment Chromatography
Paper chromatography is a technique used to separate a mixture into its
component molecules. The molecules migrate, or move up the paper, at
different rates because of differences in solubility, molecular mass, and
hydrogen bonding with the paper.
For a simple, beautiful example of this technique, draw a large circle in the
center of a piece of filter paper with a black water-soluble, felt-tip pen. Fold
the paper into a cone and place the tip in a container of water. In just a few
minutes you will have tie-dyed filter paper!
The green, blue, red, and lavender colors that came from the black ink
should help you to understand that what appears to be a single color may
in fact be a material composed of many different pigments —and such is
the case with chloroplasts.
Design of the Experiment I
In paper chromatography the pigments are dissolved in a solvent that
carries them up the paper. In the ink example, the solvent is water. To
separate the pigments of the chloroplasts, you must use an organic
solvent.
In the following activity, you
will separate plant pigments using
an organic solvent such as a
mixture of ether and acetone. Be
sure to keep the bottle tightly
closed except when you are using
it because the solvent is very
volatile and produces fumes you
should not breathe.
The next screen shows you the separation of plant pigments.
Depositing the Pigment
Pigment Separation (time-lapse view)
Lab analysis:
Analysis of Results I
If you did a number of chromatographic separations, each for a different
length of time, the pigments would migrate a different distance on each run.
However, the migration of each pigment relative to the migration of the
solvent would not change. This migration of pigment relative to migration of
solvent is expressed as a constant, Rf (Reference front). It can be
calculated by using the formula:
Look back at the black ink
chromatogram, and then calculate the
Rf value for green.
Diffusion and Osmosis lab:
Diffusion and Osmosis
by Theresa Knapp Holtzclaw
Introduction
The processes of diffusion and osmosis account for much of the passive
movement of molecules at the cellular level.
In this laboratory, you will study some of the basic principles of molecular
movement in solution and perform a series of activities to investigate these
processes.
Key Concepts
Diffusion
Molecules are in constant motion and tend to move from regions where
they are in higher concentration to regions where they are less
concentrated. Diffusion is the net movement of molecules down
their concentration gradient. Diffusion can occur in gases, in liquids, or
through solids. An example of diffusion in gases occurs when a bottle of
perfume is opened at the front of a room. Within minutes people further and
further from the source can smell the perfume.
Osmosis is a specialized case of diffusion that involves the passive
transport of water. Inosmosis water moves through a selectively permeable
membrane from a region of its higher concentration to a region of its lower
concentration. The membrane selectively allows passage of certain types
of molecules while restricting the movement of others.
Closer Look: Osmosis
The solute concentration in the beaker is higher than that in the bag, and
thus the water concentration is lower in the beaker than in the bag. This
causes water to move from the bag (left) into the beaker (right).
Movement of Molecules in Solution
There are often several different types of molecules in a solution. The
motion of each type of molecule is random and independent of other
molecules in the solution. Each molecule moves down its own
concentration gradient, from a region of its high concentration to a region of
its low concentration.
Though the net movement of molecules is down their concentration
gradient, at any time molecules can move in both directions as long as the
membrane is permeable to the molecule. Keep this in mind while you take
a closer look at the beaker below.
Closer Look: Concentration Gradient
Notice that the starch molecules are too large to pass through the pores in
the membrane. The iodine molecules move across the membrane in both
directions, but their net movement is from the bag, where their
concentration is higher, into the beaker, where their concentration is lower.
The iodine combines with starch to form a purplish-colored compound.
The net movement of water is into the beaker.
Movement of Molecules in Cells
Like dialysis bags, cell membranes are selectively permeable. As you view
the next animation, watch for the selective property of the cell membrane
and the two-way diffusion of molecules. Finally, notice the net movement of
the molecules.
The movement of water is influenced by the solute concentrations of the
solutions. Let's review the different types of solutions.
Types of Solutions Based on Solute Concentration
The terms hypotonic, hypertonic, and isotonic are used to compare
solutions relative to their solute concentrations.
In the illustration, the solution in
the bag contains less solute than
the solution in the beaker. The
solution in the bag
is hypotonic(lower solute
concentration) to the solution in
the beaker. The solution in the
beaker ishypertonic (higher solute
concentration) to the one in the
bag. Water will move from the hypotonic solution into the hypertonic
solution.
In this illustration the two
solutions are equal in their solute
concentrations. We say that they
are isotonic to each other.
Will there be a net movement of
water between two isotonic
solutions?
Yes
No
Water Potential
The water potential of pure water in an open container is zero because
there is no solute and the pressure in the container is zero. Adding solute
lowers the water potential. When a solution is enclosed by a rigid cell wall,
the movement of water into the cell will exert pressure on the cell wall. This
increase in pressure within the cell will raise the water potential.
Look again at the equation for water potential:
Water potential ( ) = pressure potential ( ) + solute potential ( )
There are two components to
water potential: solute
concentration and pressure. How
do you think this fact affects the
movement of water into and out of
cells? For example, can two
solutions that differ in their solute
concentration be at equilibrium in
terms of water movement? Can a
solution with a molarity of 0.2 be in
equilibrium with a solution with a
molarity of 0.4?
Yes
No
Cell Respiration
by Theresa Knapp Holtzclaw
Introduction
http://www.phschool.com/science/biology_place/la
bbench/lab1/intro.html
http://www.phschool.com/science/biology_place/la
bbench/lab4/intro.html
Cellular respiration occurs in most cells of both plants and animals. It takes
place in the mitochondria, where energy from nutrients
convertsADP to ATP. ATP is used for all cellular activities that require
energy.
In this laboratory, you will observe evidence for respiration in pea seeds
and investigate the effect of temperature on the rate of respiration.
Design of the Experiment
How can the rate of cellular respiration be measured? When you study the
equation for cellular respiration, you will see that there are at least three
ways:
1. Measure the amount of glucose consumed.
2. Measure the amount of oxygen consumed.
3. Measure the amount of carbon dioxide produced.
In this experiment, we are going to measure the amount of oxygen
consumed.
Features and Functions of a Respirometer
This illustration shows you the basic features of a respirometer. It will
measure changes in gas volume related to the consumption of oxygen.
You can construct a respirometer by putting any small organism in a vial
with a pipette attached. This example uses a cricket; in the laboratory
experiment, you will use peas. Remember, cellular respiration occurs in the
cells of both animals and plants!
How the Respirometer Works
When the tip of the respirometer is submerged, no additional air will enter.
As O2 is used up, the
pressure of gases
inside the respirometer
decreases. This causes
water to enter the
pipette.
The CO2 that is produced combines with KOH to form a solid precipitate,
K2CO3.
Notice that as the gas volume inside the vial decreases, the pressure of
water outside the vial forces water into the pipette. Because the amount of
water that enters the pipette is directly proportional to the amount of oxygen
consumed by the cricket, measuring the water volume in the pipette allows
you to measure the rate of respiration.
Assembling the Respirometer
In this experiment you will compare the rate of respiration in peas that are germinating to the rate in
peas that are dormant (dry peas). You will make the comparison at two different temperatures: 10°C
and 25°C. In addition, you will compare these rates to a nonmetabolizing control.
Why is it important to have a control?
The following illustration shows you how to assemble a respirometer.
It is important that the three vials contain an equal volume of contents. You do this by adding glass
beads to the vial with the dormant peas, since the dry peas take up less space than an equal quantity
of germinating peas.
Note: Because you are measuring the rate of respiration at two different temperatures, prepare two
sets of three vials.
Lab
Hints
1. You will need to use a layer of nonabsorbent cotton between the KOH and the
peas.
2. The stopper must be firmly inserted for an air-tight seal. Check that no peas or
beads block the opening to the pipette.
3. Let the respirometers equilibrate for several minutes in their respective
waterbaths. This will minimize volume changes due to change in air
temperature.
More Information on Germinating Peas
Seeds contain a plant embryo and its initial food supply protected by a seed coat. When warmth and
moisture conditions are favorable, germination, or sprouting, will begin. When you soak pea seeds for
this laboratory, germination begins. Enzymes begin using the stored food supply to generate ATP, and
the rate of cellular respiration accelerates.
It is important to know that nongerminating seeds are not dead; they are dormant. Do they respire?
Measuring the Rate of Respiration
Gas volume is related to the temperature of the gas. According to the gas law
(V=nRT/P) , a change in temperature will cause a direct change in volume. Because
the temperature in the respirometers may vary during the course of the
experiment, you must correct for differences in volume that are due to temperature
fluctuation rather than rate of respiration. To do this, subtract any difference in the
movement of water into the vial with glass beads from the experimental vials held
at the same temperature. Record the result as the corrected difference.
http://www.phschool.com/science/biology_place/labbench/lab5/intro.html
Membranes allow cells to create and maintain internal environments that
are different from the external environments. The structure of the cell
membrane results in selective permeability. The movement of molecules
which can occur either through diffusion or osmosis.
Organisms also have feedback mechanisms that maintain dynamic
homeostasis by allowing them to respond to changes in their internal and
external environments.
Negative feedback loops maintain internal environments, and positive
feedback amplifies responses. A good example of negative feedback would
be your blood sugar levels. When your blood sugar level is too high, insulin
is released so that it can lower the amount of sugar in your blood, and
when your blood sugar level is too low, glucagon is made so that it can
increase the amount of sugar in your blood. An example of positive
feedback on the other hand, would be a woman who is pregnant with a
baby. When a woman is pregnant she has constant pains that are called
contractions, and when she gives birth, those contractions increase instead
of decreasing.
Cells and organisms have to exchange matter with their environment.
Water and nutrients for example are used in the synthesis of new
molecules. The carbon moves from the environment to organisms where
it's incorporated into carbohydrates, proteins, nucleic acid, or fats.
Major points of Big Idea Two:
Growth, reproduction, and maintaining organization of living systems
require energy and matter.
Growth, reproduction,and homeostasis require that cells create and
maintain internal environments that are different from their external
environments.
Organisms use feedback mechanisms to regulate growth, and maintain
homeostasis.
Growth and homeostasis of a biological system are influenced by changes
in the systems environment.
Many biological processes involved in growth, reproduction, and
homeostasis include temporal aspects.
Energy is the ability to do something. There are two general types of
energy, and that is kinetic and potential energy. Potential energy is the
ability to store something. Potential energy is the result of gravity pulling
downwards. An example would be the heavy ball of demolition machine,
storing energy when it’s held at an elevated position. Types of potential
energy are, nuclear, electrical, chemical, nuclear, and gravitational.
Chemical energy is potential energy that’s available for release in a
chemical reaction. To find the potential energy of a product, you use this
equation:
Potential Energy Formula:
Potential Energy: PE = m x g x h
Mass:
Acceleration of Gravity:
Height:
where,
PE = Potential Energy,
m = Mass of object,
g = Acceleration of Gravity,
h = Height of object,
<http://easycalculation.com/physics/classical-physics/learn-potential.php>
A Potential energy problem from the link I put up there:
Potential Energy Example:
Case 1: A cat had climbed at the top of the tree. The Tree is 20 meters high and
the cat weighs 6kg. How much potential energy does the cat have?
m = 6 kg, h = 20 m, g = 9.8 m/s2(Gravitational Acceleration of the earth)
Step 1: Substitute the values in the below potential energy formula:
Potential Energy: PE = m x g x h
= 6 x 9.8 x 20
Potential Energy: PE = 1176 Joules
While Kinetic energy is, the energy that a body possesses by virtue of
being in motion. Types of kinetic energy are moving objects, radiation,
thermal, and electrical. Heat or thermal energy is kinetic energy associated
with random movement of atoms or molecules. Kinetic energy is a property of
a moving object or particle and depends not only on its motion but also on its
mass. An example of kinetic energy would be, a man running. This is kinetic
because the man is moving. To find the kinetic energy of a product, you
have to use a formula:
Where m = mass of object
v = speed of object
A kinetic energy problem:
Determine the kinetic energy of a 625-kg roller coaster car that is
moving with a speed of 18.3 m/s.
Use the formula that I put up there!:
The way to solve it:
So the formula is:
M being the mass of the object, and V being the velocity, so you just plug in
the numbers to find the answer. :
KE = 0.5*m*v2
KE = (0.5) * (625 kg) * (18.3 m/s)2
KE = 1.05 x105 Joules
Then there are the laws of thermodynamics:
The first law states that, energy is never created or destroyed, energy is
transformed from one form to another, and winds motion is converted to
electricity, which is then converted to heat, and light bulb energy in a light
bulb.
The second law states that the entropy of an isolated system is always
increasing (entropy is an amount of energy in a form that’s unusable.
Usually this form can be heat.), and that systems are always losing forms
of energy that are useable.
This means that in every conversion of energy, a lot of the energy is lost as
heat. Energy spreads from areas of high energy to low energy. An example
of this would include, heat being transferred from a hot pan to the air
around it.
Exergonic and Endergonic reactions:
An exergonic reaction is a chemical reaction where the change in the Gibbs
free energy is negative, meaning that this is a spontaneous reaction. In an
exergonic reaction, energy is being lost during the process of the reaction.
Activation energy catalyzes the reaction to make it occur in a spontaneous
manner. The change in the Gibbs free energy in an exergonic reaction has
a negative value, because energy is lost.
The Gibbs free energy of a system is defined as the enthalpy of the
system, minus the product of the temperature, times the entropy of the
system. <http://chemed.chem.purdue.edu/genchem/topicreview/bp/ch21/gibbs.php>
Free energy is used to maintain body temperature for some organisms,
reproduction, growth, and development.
To find it, you use this formula:
An endergonic reaction on the other hand is a chemical reaction in which
the standard change in free energy is positive, and energy is absorbed.
<http://en.wikipedia.org/wiki/Endergonic_reaction>
An endergonic reaction is a reaction that requires energy to drive the
reaction. The activation of that energy is larger than the requirement for the
exergonic reaction because energy is consumed in the process of the
reaction. Unlike exergonic reactions, endergonic reactions are not
spontaneous.
Cellular respiration for example is an endergonic reaction, because it has
this amount of energy that’s required, in making ATP.
Just a couple of random things that you should know, involving big idea
two:
Ninety nine percent of all living matter is made up of, Nitrogen, Carbon,
Hydrogen, and Oxygen. Cells that are damaged or infected have what’s
called a programmed cell death which is apoptosis. Apoptosis protects
neighboring cells from damage that they would suffer and allows molecules
to be reused. It also helps maintain homeostasis.
For body temperature regulation, there are endothermic and exothermic.
Endothermics use heat released by metabolic reactions to keep a stable
temperature. Endothermics include humans.
While exothermics use external sources to try and maintain body
temperature. These include snakes and reptiles.
Reproduction on the other hand requires a lot of energy. Fact: Most
species only reproduce when energy is available. Example: plants. Most
plants flower in the spring when there is a lot of sunlight energy.
When energy deprivation occurs, mass is broken down to provide energy. If
there for some reason, isn’t any energy input, then death will occur
eventually.
Smaller organisms have more surface area relative to their volume, so they
lose more heat. To replenish that energy loss they tend to eat more than
larger animals.
In trophic levels:
Energy works its way up the food chain.
At every energy level though, energy is being lost due to entropy, which
means that there’s less energy available for the higher levels in the food
chain.
The reason that most animals become endangered is because, there’s very
energy left for them.
Apoptosis during paw development: apoptosis eliminates the cells in the
interdigital regions forming the digits.
Now onto bonds:
Hydrogen bonds facts:
The partial negative charges on oxygen attracts partial positive charge on
hydrogen atoms.
Impacts most of waters properties.
In cohesion, water molecules stick to each other. The water can be pulled
as each molecule pulls on the molecule next to it.
Adhesion is when water can also stick to other charged surfaces. This is
important when it comes to plants being able to take in water.
In surface tension, hydrogen bonds cause water to have a high surface
tension or a surface that’s hard to break. It’s measured as the energy
required to increase the surface area of a liquid by a unit of area. The
surface tension of a liquid can result from an imbalance of intermolecular
attractive forces, also known as the cohesive forces, between molecules.
Capillary action is the ability of a liquid to flow in narrow spaces without the
resistance and the opposition of external forces such as gravity. It results in
the elevation or depression of liquids in the capillaries.
Specific heat is a measure that’s used in Thermodynamics that states the
amount of energy that’s necessary to raise the temperature of a given
mass of a particular substance by some amount. <http://www.wisegeek.org/whatis-specific-heat.htm>
“ While different scales of measurement are sometimes used, this term
usually specifically refers to the amount required to raise 1 gram of some
substance by 1.8°F (1° Celsius) or by 1 Kelvin — 1 Kelvin is the same as
1°C. It follows that if twice as much energy is added to a substance, its
temperature should increase by twice as much. Specific heat is usually
expressed in joules, the unit typically used in chemistry and physics to
describe energy.” <http://www.wisegeek.org/what-is-specific-heat.htm>
Evaporative cooling facts:
Water has a high heat of evaporation.
Evaporating water takes up a lot of energy.
The reason that sweat cools us off is because the hottest molecules
evaporate first.
Evaporative cooling is the reduction in temperature resulting from the
evaporation of a liquid. As a result, this removes heat from the surface.
The Big question! Ice Float facts:
Most solids are most dense than liquids. When ice floats, the H bonds
become locked, keeps the rest of the lakes and rivers from freezing, and it
warms the rest of the water. A substance floats if it’s less dense, or has
less mass per unit volume, than other components in a mixture. Water
reaches its maximum density at 4 degrees Celsius, which is 40 degrees
Fahrenheit. As it cools more and more, and turns into ice, it becomes less
dense, while most substances are denser in their solid state, instead of
their liquid states.
A water molecule is made from one oxygen atom and 2 hydrogen atoms,
joined together by a covalent bond. Water molecules can also be attracted
to each other by weaker hydrogen bonds between the positively charged
hydrogen atoms, and negatively charged oxygen atoms of neighboring
water molecules. As the water cools below 4 degrees Celsius, the
hydrogen bonds adjust to hold the negatively charged oxygen atoms away
from each other. This then produces ice. The ice floats because it’s 9%
less dense then the liquid water. The heavier water displaces the lighter
ice, which causes the lakes and rivers to freeze from top to bottom,
allowing the fish to survive even when the surface of the lake is completely
frozen. If the ice sank, then the water would be on moved to the top, and
exposed to the colder temperatures, forcing rivers and lakes to fill with ice,
and become frozen solid. This would end up killing many animals who’s
habitats are in that water, because they would not be used to that kind of
temperature.
Functional groups:
Functional groups, are specific groups of atoms or bonds within molecules
that are responsible for the chemical reactions of those molecules.
Some functional groups to remember:
A hydroxyl group is oxygen containing group based on an alcohol or OH
group. They are known as the alcohols, and are polar.
A polar molecule is a molecule that has a mostly positive charge on one
side, and a mostly negative charge on the other side. The difference in this
charge allows the positive end to attract the negative end, to one another.
A carboxyl group is a functional group that consists of a carbon atom joined
to an oxygen atom, by a double bond, and to a hydroxyl group by a single
bond.
“Carboxyl groups frequently ionize, releasing the H from the hydroxyl group
as a free proton (H+), with the remaining O carrying a negative charge. This
charge "flip-flops" back and forth between the two oxygen atoms, which
make this ionized state relatively stable. (Hydroxyl groups sometimes
ionize momentarily, but the resulting ionic forms are not stable and the ions
immediately rejoin.)
Molecules containing carboxyl groups are called carboxylic acids and
dissociate partially into H+ and COO–. “
<http://www.phschool.com/science/biology_place/biocoach/biokit/carboxyl.html>
Amino groups are known as amines, and act as a base accepting protons.
They are an essential part of amino acids. It consists of a nitrogen atom
attached by single bonds to a hydrogen atom, alkyl groups, aryl groups, or
a combination of the three. An aryl group is a group of atoms derived from
benzene or from a benzene derivative, by removing one hydrogen that is
bonded to a benzene ring. Benzene is a colorless, flammable toxic liquid.
It’s a hydrocarbon with formula C6H6. Alkyl groups on the other hand are a
group of carbon and hydrogen atoms derived from an alkane molecule by
removing one hydrogen atom.
Amino acids are organic compounds that consist of both a carboxyl group
and an amino group.
Sulfhydryl Group:
Like oxygen, sulfur typically has a valence of 2, although it can also have a
valence of 6, as in sulfuric acid.
Sulfur is found in certain amino acids and proteins in the form of sulfhydryl
groups (symbolized as -SH). Two sulfhydryl groups can interact to form a
disulfide group (symbolized as -S-S-).
Sulfhydryl groups are involved in stabilizing proteins.
Phosphate group:
Phosphate groups are strongly negatively charged, they are hydrophilic,
and are found in DNA and RNA.
“Phosphate groups can be joined together to form phosphodiester bonds.
Phosphate groups can also be joined to other molecules, such as sugar.
When phosphate is added to a nucleoside, the molecule is called a
nucleotide.” <http://www.phschool.com/science/biology_place/biocoach/bioprop/phosphat.html>
Macromolecules:
Polymers:
1. Long chain of monomers
2. Takes energy and involves removal of water
Hydrolysis:
Macromolecules are split apart by water. It releases new energy. A
macromolecule is a molecule containing a very large number of atoms.
Carbohydrates:
They are simple sugars, disaccharides, and polysaccharides. These
include starch, glycogen, cellulose, and chitin.
Disaccharides are carbohydrates created by two monosaccharides.
Polysaccharides are a carbohydrate whose molecules consist of a number
of sugar molecules bonded together.
Monosaccharides are any class of the sugars that cannot be hydrolyzed to
give a simpler sugar.
Starch: An odorless tasteless white substance occurring widely in plant
tissue and obtained chiefly from cereals and potatoes. It is a
polysaccharide.
Glycogen: A substance deposited in bodily tissues as a store of
carbohydrates; a polysaccharide that yields glucose on hydrolysis.
Cellulose: An insoluble substance that is the main constituent of plant cell
walls and of vegetable fibers such as cotton. It is a polysaccharide.
Fact: You can’t digest cellulose
Carbs facts:
It’s the way that organisms store sugars
They are made of simple sugars by dehydration reactions.
They are important in plant cell walls.
Saturated V. Non Saturated:
 Saturated = all single bonds in the hydrocarbon tail
 Straight chain
 Solid at room temperature
 Most animal fats
 (lard, butter)
 Unsaturated = at least one double bond
 Kink in chain
 Liquid at room temp
 Called oils
 Found in fish and plants
They are both used for energy storage and insulation.
Amino acids:
 All proteins are made of amino acids
 Amino acids contain an amino group, a carboxyl group, an H atom
and a “variable group”
 The R group is the only thing that changes
Proteins:
 Structural support, storage, transport, signaling, movement, defense,
enzymes etc.
 There are tens of thousands of different proteins in the body
Proteins make up amino acids.
In the Carbon cycle:
• Taken in during photosynthesis
• Center of almost all molecules made in plant
• Animals obtain by eating carbon-based foods
Other things to know: