Download a short review of biology I

a short review of biology I
1. what does it mean to be alive
2. basic chemistry
3. what goes on in a cell
4. basic genetics
5. cell division (mitosis & meiosis)
Carol is a college student
Carol eats pizza
all college students eat pizza
Is this always true – NO
this is INDUCTIVE REASONING
BUT
all men are mortal
Tom is a man
Tom is mortal
is this always true = YES
this is deductive reasoning
Carol is a college student
Carol eats pizza
all college students eat pizza
Is this always true – NO
this is INDUCTIVE REASONING
BUT
the thousands of pages written by Darwin can be
summarized in a simple statement
the rearrangement of genes
that takes place every time an egg and sperm are made
can result in an advantage for survival and reproduction
which over time will spread through a population
and can change a population so that
it no longer looks like it’s ancestors
Darwin concluded that what he was seeing was
1)the result of an animal from one environment moving into a
new environment and 2)changing slowly over time through
sexual reproduction to become 3) more adapted to the new
environment and 4) more sexually successful
in the new different environment
the changes in color, anatomy, size, physiology, and more over
time produced a very different organism
or
an organism can change in its present environment to become
more successful (pass on its genes= have more sex)
when protons are equal to electrons - neutral atom
when protons do not equal electrons – atom is an ion
if there are more protons than electrons – positive cation
if there are more electrons than protons – negative anion
electrons determine the chemical behavior of atoms
how
when the outer electron shell of an atom is not full
it will give away electrons,
or get electrons from other atoms,
or share electrons with other atoms
in order to have the outer shell filled
carbon has 4 electrons in its outer shell
two carbons share their outer 4 electrons
making an outer shell in each atom with 8 electrons
thus each has a full outer shell with 8 electrons
forming a covalent bond
the electrons travel so fast that it is as if
the 8 electrons are in both atoms at the same time
the ability of atoms to form chemical bonds
is influenced by
- temperature (2x for every 10C)
- concentration
-catalysts (enzymes)
- pressure (keeps atoms closer together)
I will on many occasions mention the
shape of a molecule
why
because molecules cannot talk to each other
molecules cannot use a phone to tell you something
so
molecules react according to their shape
they fit together like pieces of a puzzle
message to cell – membrane carries message to cytoplasm
- series of chemical changes take place in cytoplasm (transduction)
- changes carry message to nucleus
- in nucleus message cause 1 gene to unwind
- DNA of gene makes a copy of the gene
- the copy is known as messenger RNA (mRNA)
-mRNA leaves the nucleus
-mRNA stimulates RER to make a protein (enzymes and more)
- enzyme tells cell what work to do
at every step chemicals fit together like pieces of a puzzle
if the pieces do not fit the process stops
DEHYDRATION
when 2 molecules are joined together
to form a larger compound
a H is removed from 1 reactant
and an OH is removed from the 2nd reactant
resulting in
the formation of a molecule of water
the reactants were dehydrated water was removed
from the reactants and is now free in the cell
HYDROLYSIS
when a large molecule is being split by an enzyme
then
water is split to H and OH
the H is added to one part
and OH is added to the other part
water was split and the subunits were added to
the hydrolyzed compound
resulting in the loss of a water molecule
from the cell
proteins have many functions
-as enzymes-tell the cell what work to do
-defense-fight infection and disease
-transport-oxygen, hormones, through membranes
-support-hair, skin, bone, muscle,
-motion-muscles, tendons, ligaments, mitosis, meiosis
-regulation-hormones, enzymes, gene activation
-storage- calcium, iron, oxygen
Proteins can be
enzymes
hormones
transporters
immune modulators
receptors
structural
energy storage
motion
the cell theory
1. all living things are made up of one or more cells
2.cells are the basic building block of all organisms
3. cells come from other cells
cells are small because
of the ratio between
surface area compared to volume
surface area is represented
by the cell membrane
volume is represented
by the cytoplasm (liquid in the cell)
and it’s contents
as a cell grows the
surface area increases
but not as fast as the cytoplasm inside the cell
eventually
the cell becomes too big
and
the cell membrane can no longer keep up
with the needs of the inside of the cell
and this becomes the stimulus for the cell
to divide and become two smaller cells
prokaryotes
primitive cells
- a simple but effective structure
- one (1) strand of DNA some have a second
- cell membrane and cell wall
- move by pili and flagella
- pili also used for attachment and gene exchange
- have free ribosomes
- no membrane bound organelles
- no nucleus
scavengers, carnivores, photosynthetic, decomposers
eukaryotes
advanced cells
compartmentalized organelles
nucleus protects genetic material
internal endomembrane system
internal transport system
you have eukaryotic cells in your bodies
DNA contains the genetic code(for many genes)
one gene makes one kind of RNA
mRNA goes to the cytoplasm and a protein is made
many of the proteins are enzymes
there are thousands of mRNAs
rRNAs form ribosomes in the cytoplasm (protein factories)
tRNAs bring amino acids to ribosomes to make up a protein
the enzymes then link up with other
cell components and cause the chemical reactions
of those components to work millions of times faster
then when the enzymes are not present
in other words enzymes tell the cell what
work to do
when done the enzymes are recycled
completed products from the RER, SER or free ribosomes
are secreted as transport vesicles
which
fuse with the Golgi apparatus
materials enter the Golgi apparatus
from the RER and the SER
as transport vesicles
are rearranged
and are packaged
(made ready for delivery to where they are needed)
these products are pushed out of the Golgi
at the ends of the membranes (cisternae)
in the from of secretory vesicles
the vesicles which leave the Golgi
can be used outside of the cell
or in the cell
many secretory vesicles combine with the cell membrane and
by exocytosis are moved out of the cell
in order to survive
a cell needs energy
mitochondria
produce
a high energy phosphate molecule
known as ATP
adenosine tri phosphate
which produces
the energy used by cells to do work
the inside of a cell is a thin Jello-like cytoplasm
the cell membrane is a thin layer of phospholipid
if this was all that a cell had the cell would collapse
but
a cell has a cytoskeleton
a series of
actin filaments, microtubules, and intermediate filaments
which allow a cell to retain a circular shape
many of the cells components
are organized into functional complexes
organelles, enzymes, microbodies,
molecular motors and more
are
in close proximity to each other so that
all of the things needed to do work are
right next to each other
a cell membrane is much more than a simple skin
animal cells secrete an
extracellular matrix
which is made up of
fibrous proteins (collagen)
glycoproteins (receptors, transporters)
elastin (membrane strength & shape)
integrins (chemical & mechanical signals)
which cover the outside of the cell membrane
-a chemical is floating in the liquid outside a cell
-a membrane projection links up with the chemical
-causes change in shape of a membrane chemical
-cause chemical change in cytoplasm
-change eventually causes chemical change in nucleus
-one gene is opened up and copied as mRNA
-mRNA leaves nucleus links up with ribosome
-ribosome makes proteins and enzymes
-enzyme stimulates 1 chemical reaction to work very fast
-product goes to Golgi for rearrangement and packaging
-Golgi releases vesicle which is moved by molecular motor
-vesicle use in cell or is moved out of cell
cell junctions
cells that are next to each other
interact with each other
adhere to each other
communicate with each other
see fig. 6.30 page 120
tight junctions = two cell membranes glued together
desmosomes = rivets or screws holding two cell membranes
close to each other allowing some movement
gap junctions = connects the cytoplasm of adjacent cells
allowing material to move between the cells
cell membrane protein functions
are very important
-transport (in & out of cell)
-enzymes (many reactions on & in membrane)
-surface receptors (chemical puzzle pieces)
-surface identifiers (shows who the cell is)
-adhesion (temporary & permanent attachments)
-cytoskeleton (intra & inter connections)
end result of diffusion
is always equilibrium
when the molecule concentration is equal
on both sides of a membrane
molecules move in and out at same rate
so
once equilibrium is reached the
concentration remains the same
which way water will move
is determined by the
concentration of
water as a solvent and
various chemicals as solute
for example
water will move across the membrane
from
an area of higher water concentration
to
an area of lower water concentration
until
the concentration of water
is
equal on both sides of the membrane
isotonic = solute concentration the same on both sides
hypotonic = side with less solute concentration
hypertonic = side with more solute concentration
active transport can move molecules
against a concentration gradient
the end result of diffusion is equilibrium
but
active transport can concentrate material
on one side of a membrane
active transport can move molecules from an area of
low concentration to an area of higher concentration
movement of material
in and out of the cell
is referred to as
-endocytosis
-exocytosis
-phagocytosis
-pinocytosis
-receptor mediated endocytosis
phagocytosis
refers to
taking in particulate matter
pinocytosis
refers to
taking in liquid
receptor mediated endocytosis
refers to
a process whereby membrane receptors
are concentrated in an area
and when
bound to a target molecule
the membrane
folds inwards into a vesicle
transporting the target molecule
into the cell
anabolic = use energy to build up
catabolic = use energy to breakdown
heat = energy moves from one item to another
chemical energy = potential energy available from chemical reactions
pathways = steps from raw material to finished product
metabolism = chemical reactions of an organism
ATP has 3 phosphate bonds
each is a positive functional group
to keep a 2nd group in place requires some energy
but to keep a 3rd positive bond attached
requires
a large amount of energy
when
the energy of the 3rd bond (high energy bond)
is released it is used to do work
enzymes are not destroyed
when they are used to do work
they
are used over and over
until they are not needed
then
they are recycled
in order to make the chemistry
of cells more efficient
enzymes needed to accomplish
a specific task are
part of a
multienzyme complex
all of the enzymes needed for one job are
right next to each other so that the
individual steps needed to form a product
take place right next to each other
remember that most biological reactions involve
oxidation or reduction
oxidation = loss of an electron
reduction = gain of an electron
electron donor = reducing agent
electron acceptor = oxidizing agent
aerobic = in presence of oxygen
anaerobic = without oxygen
glycolysis is a three step process which takes place in
the cytoplasm of ALL cells
it starts with glucose and ends with
2 molecules of pyruvate (acidic)
2 ATP
2 molecules of NADH
2 H+ (acidic)
and 2H20
pyruvate also known as pyruvic acid
must not be allowed to build up
in a cell
in primitive organisms pyruvate
is broken down by
fermentation
to produce products which will
not harm the cell
in eukaryotic cells
pyruvate enters mitochondria
and pyruvate is oxidized in a multienzyme complex
to acetyl coenzyme A
and CO2 and NADH are produced
(see fig. 9.11)
pyruvate + NAD++ CoA  acetylCoA + NADH + CO2 + H+
we have 46 chromosomes
23 from mom
23 from dad
the only time that we can actually
get to see the 46 chromosomes
is during cell division
we have 46 chromosomes
23 from mom
23 from dad
the only time that we can actually
get to see the 46 chromosomes
is during cell division
the cell cycle consists of
1. interphase (not part of mitosis)
2. prophase
3. metaphase
4. anaphase
5. telophase
6. cytokinesis
gametes = eggs and sperm
eggs and sperm = haploid (half a set)
somatic cells = diploid (full set)
what do you inherit? – genes
what are genes = messages for what a cell should do
where are genes located? – on chromosomes
what do we pass on to the next generation?
genes
mutations
variations of combinations
it is as if you took a few thousand genes
which occur as pairs and you rearranged
them randomly and for the fun of it
you see what happens
1. double the chromosomes (4 become 8)
2. form tetrads
3. exchange genes
4. line up at midplate
5. pull apart chromosomes so sister chromatids are intact
6. cell becomes 2 cells(each with 4 chromosomes)
7. sister chromatids in 2 cells line up at midplate
8. sister chromatids pulled apart
9. 2 cells become 4 cells each with 2 chromosomes
dominant = if gene is present trait will be seen
recessive = dominant gene must be absent for trait to be seen
pure = both genes for a trait are identical
hybrid = 2 genes (alleles) for the same trait
homozygous = same as pure
heterozygous = same as hybrid
genotype = combination of genes for a trait
phenotype = result of a genotype
P = parent organism
F1 = first generation after the P generation
F2 = result of cross of F1 with F1
Gregor Mendel
is called the
Father of genetics
because he came up with the idea
that organisms carry
a pair of “something” for each trait
and that
we only pass on 1 of these “somethings” to our offsprings
here is what Mendel did
1. he chose specific traits in pea plants
2. he took plants which he knew were pure breeding
3. then he crossed them with other pure breeding plants
4. and he saw what the F1 generation looked like
5. then he crossed F1 with F1 and saw what the F2 looked like
6. but unlike others he did it quantitatively
7. he was lucky that all of the traits he chose were
controlled by a single pair of genes
1. he made sure he had pure breeding plants
2. he crossed pure with same pure
3. he crossed pure with different pure
4. he crossed non pure with non pure
5. most important he recorded the numbers
and here is what he got
what he concluded was that
whatever was controlling the traits
came in pairs
that each parent gave one of the pair to its offsprings
that a parent can have an identical pair
or a parent can have a non-identical pair
he concluded that whatever was passed on
was discrete (it was a thing) although
he had no idea what it was
Mendel’s 5 element model
1. parents pass on “factors” to their offsprings
2. each offspring gets one copy of the “thing” from each parent
3. the “things” come in 2 different forms
4. the “things” remain separate and do not affect each other
5. presence of a “thing” does not guarantee it’s expression
Principle of Segregation
two alleles for a gene/trait
segregate during gamete formation
and are rejoined at random
one from each parent
during fertilization
there is no plan which controls which one of the
two “things” will end up in an egg or sperm
it is random