Download The Scientific Method

-The organized way that
scientists solve problems
- consists of very specific steps
Hypothesis - an
“educated”
guess, or one
which occurs
after researching
Important in experiment design:
- Useful experiments have only 1
variable.
Variable - factor being tested
control - experiment without the
variable.
- Useful experiments collect enough
data or observations to draw a
conclusion.
Observations – what happened
during the experiment that was
seen, smelled, tasted, felt, or
heard
Data - recorded measurements of
changes that occurred during
the experiment
Data tables – charts the represent
data neatly and clearly
Graphs – bar graph, line graph,
pie graph, or whatever kind of
graph would properly represent
the data
A theory is the most logical explanation about events
that occur in nature. It has been tested repeatedly.
Law - if a theory holds up after a long time
There are two versions of the idea
• Spontaneous Generation/Abiogenesis:
Life forms can arise spontaneously from
non-living matter.
• Biogenesis: Living things can only come
from other living things.
Which is true?
All living things are made up of cells.
• Cells are the smallest
units of an organism that
can be considered alive.
• Some organisms are
unicellular (made of 1
cell) and some are
multicellular (made of
more than 1 cell).
All living things reproduce.
• Reproduction is the
production of new
organisms.
• Some living things
reproduce sexually (with 2
parents).
• Other living things
reproduce asexually (1
parent).
All living things need materials and
energy.
• Autotrophs get their
energy from the sun
and make their own
food.
• Heterotrophs get their
energy from their
food.
All living things maintain internal
balance.
• Homeostasis is the process of keeping
internal conditions stable.
Functions of Carbohydrates in Cells
• Used for energy
– Energy is stored in Adenosine
TriPhosphate (ATP)
•
•
•
•
Used to communicate between cells
Used to store energy
Used to provide support for cells
Made up of monosaccharides (glucose)
Testing for Carbohydrates
• The Benedicts Test is used to detect simple
carbohydrates (sugars)
• The Iodine test is used to detect complex
carbohydrates (starches)
Functions of Lipids in Cells
• long term storage of energy
• create membranes around cells to be a barrier
for a cell
– Lipids make good membranes because they are
hydrophobic (water fearing)
• lipids are base molecules for hormones
(chemical signals the body uses to direct
some of its activities)
• Tested in foods with the Sudan Test
• Made up of glycerol and fatty acids
Functions of Proteins
• Used for structure of a cell
• found in membranes - control what
goes in and out of a cell
• used to communicate with other cells
• used as enzymes (bring about a
chemical reaction in an organism)
• The Biuret test is used to detect
proteins in foods.
Enzymes
• Protein that speeds up a chemical reaction
without being used by the chemical reaction
Ecology
• The scientific study of interactions among
organisms and between organisms and their
environment
Biosphere
• The largest level of organization of the
living world
• Contains the part of the planet on which all
of life exists
• Includes land, water, and atmosphere
• Extends from 8 kilometers above the
Earth’s surface to 11 kilometers below the
surface of the ocean
Species
• One of the levels of organization
• Group of organisms so similar to one
another that they can breed and produce
fertile offspring
Population
• One of the levels of organization
• Groups of individuals that belong to the
same species and live in the same area
Community
• One of the levels of organization
• Groups of different populations of different
species that live together in a defined area
Ecosystem
• One of the levels of organization
• Collection of all the organisms that live in a
particular place, together with their
nonliving environment
Biome
• One of the levels of organization
• A group of ecosystems that have the same
climate and similar communities
Producers
• Organisms that can capture energy from
sunlight and use that energy to produce food
• Producers are also called autotrophs
because they make their own food.
Photosynthesis
• Process in which autotrophs use light
energy to power chemical reactions that
convert carbon dioxide and water into food
oxygen
• Adds oxygen to the atmosphere
• Removes carbon dioxide from the
atmosphere
Consumers
• Organisms that cannot harness energy
directly from the environment
• Get their energy from food
• Also known as heterotrophs
Groups of consumers
• Herbivores are consumers that eat only plants
• Carnivores are consumers that eat only meat
• Omnivores are consumers that eat both plants
and animals
• Detritivores are consumers, like earthworms,
snails, crabs, and mites, that feed on plant and
animal remains and other dead matter
• Decomposers are consumers, like bacteria and
fungi, that break down organic matter
Food Chain
• A series of steps in which organisms
transfer energy by eating and being eaten
• A food chain always begins with a
producer, which is eaten by an herbivore or
omnivore, which is eaten by a carnivore or
omnivore, and eventually is decomposed by
a decomposer and eaten by a detritivore.
Food Web
• A network of complex interactions that
shows the feeding relationship among the
various organisms in an ecosystem
• Links all the food chains in an ecosystem
together
Trophic Level
• Each step in a food chain or food web
• Producers are the first trophic level
• Consumers are the second, third, and higher
trophic levels
• Each consumer depends on the trophic level
below it for energy.
Symbiosis – 2 species living in a
close long term relationship
• Parasitism – one specie lives in or on
another specie and harms it
• Commensalism – one specie benefits and
the other is neither benefited nor harmed
• Mutualism – both species are benefitted
• Predation - one specie consumes the other
Cell membrane Structure
bilayer made of two layers
•Phospholipid
____________•hydrophobic
________ - the part of the cell membrane
that is water fearing
• hydrophilic
________ - the part of the cell membrane
that is water loving
mosaic model
• Fluid
_________________
model – means that
there are proteins in the cell membrane that
help with transport of substances
Cell Membrane Function
Passive transport transport of substances through the
• ___________membrane without using energy
2 types:
diffusion - movement of solute
1. ______
2. ______
osmosis - movement of water
Active transport
• _________
- transport of substances through the
membrane that are either too big or not creating
homeostasis ; requires energy
2 types:
endocytosis - brings big things in to cell
1. ________
exocytosis - takes big things out of cell
•
2. ________
Cytoplasm
___________________________
_
• Structure: jello in the cell
• Function: holds everything in place
Nuclear Organelles
Nuclear Membrane
__________________________
Structure: double membrane
around nucleus
Function: keeps things in and out
of nucleus
Nuclear Pores
________________________
__
Structure: holes in the nuclear
membrane
Function: allows large substances
to pass through nuclear
membrane
Nucleoplasm
__________________________
Structure: jello in nucleus
Function: holds nuclear
organelles in place
Nucleolus
____________________
Structure: ball of fibers
Function: produces ribosomes
Chromatin
____________________
Structure:DNA
molecule which
contains _______ - (double
strand of nucleic acids ) and
proteins
Function: contains all the
directions to make an organism
(genome)
Cytoplasmic Organelles
Vacuole/Vesicle
__________________
Structure: membrane
enclosing either
food or waste or
water
Function: storage of
food or waste or
water
Ribosome
________________
Structure: combination of
RNA
________
(single strand of
nucleic acid) and other
proteins; found either
floating freely or attached
to other organelles
Function: make
proteins
_________
from the
directions found in DNA
Cytoplasmic Organelles
_______________________________
Mitochondria
continued
Structure: bean shaped organelles with two membranes;
contain matrix (fluid) and cristae (folds in inner layer)
respiration
Function: cellular ______________________
Endoplasmic Reticulum
_______________________________________
Structure: system of membranes throughout the cell;
rough (contain ribosomes) and smooth
proteins
Function: RER – transports _________________,
lipids
SER – transports
__________ and
______________
fats
Cytoplasmic Organelles
continued
Golgi
Apparatus
____________
Vacuoles
_________
Structure: flat
Structure:
membrane
membrane
sacs
sacs formed
from the
Function:
membranes
package
of other
molecules to
organelles
be moved to
other parts of Function: store
the cell
food and
water
Lysosome
_______________
Structure: sacs
with enzymes
Function: help the
cell digest large
molecules so it
can use them
–
organelles that help the cell in movement
________________________
Cytoskeleton
1. _______________________________
microfilaments
Structure: fibers made of ball shaped protein called actin connected in long strings
Function: move the whole cell around
2. ________________________________
Intermediate filaments
Structure: long, string like proteins that coil together like rope to form rods
Function: add strength to the shape of the cell
microtubules
3. ___________________________________
Structure: ball shaped proteins called tubulin that come together to form a hollow
tube
Function: supports the cell’s shape; used to move organelles around
May extend out of the cell membrane and form:
cilia
a. _______________________
– small hair like structures made of microtubules;
aid in movement of some cells
b. ________________________
– long, tail like structures made of microtubules;
flagella
aid in movement of some cells
Cytoplasmic Organelles Only in Plant Cells
Cell wall
plant
Structure: only in __________
cells; made of complex
carbohydrate called cellulose;
contain plasmodesmata (openings
to communicate with other plant
cells)
Function: makes the cell firm
Central vacuole
Structure: large central vacuole
Function: storage of
__________________
water
Chloroplasts
________________________
Structure: contain chlorophyll
stroma
•Contain ________________
(fluid in inner membrane where
photosynthesis takes place)
•Contain _______________
thylakoids
(membrane sacs that contain
chlorophyll in stroma)
grana
•______________________
(stacks of thylakoids inside
chloroplasts)
Function: trap energy by
absorbing it from sunlight;
photosynthesis
Robert Hooke
• 1665
• looked at cork
• found that the interior of
cork is made of an
ordered collection of
little boxes that he called
cells
• First person to use the
word “cell”
Anton von Leeuwenhoek
• 1675
• first person to
view living cells
under a
microscope
• “animalcules”
The Cell Theory
•Developed in the 1800s
•Developed by: Schleiden, Schwann and
Virchow
•3 parts to the Cell Theory:
1. All living things are made of cells.
2. Cells are the basic units of structure and function
in living things.
3. Cells only come from already present cells.
Prokaryotic cells
• have only one membrane that separates the
cell from the outside world
• everything else floats freely inside the cell
• Ex: bacteria
• reproduce using binary fission reproduction in which a bacterial cell
divides into two cells that look the same as
the original cell
Eukaryotic Cells
• organisms with several internal structures
that are surrounded by a membrane,
including the nucleus
• Ex. Plants, animals, fungi, protists
HOMEOSTASIS
=
ISOTONIC
=
EQUILIBRIUM
biological balance with the cell’s surrounding
environment; the amounts of molecules inside
and outside the cell are kept at certain levels to
maintain a balance.
Semi-Permeable Membrane
___________________________________
– a membrane that allows some molecules to
pass but blocks other molecules from coming
through
Concentration Gradient
• a difference in the concentration of a
substance across a membrane; forms when
different concentrations of a molecule are
on either side of a membrane. Cells use this
to direct some of their activities.
Solute
• ________________________ – a dissolved
substance
HYPOTONIC – the area (inside
or outside the cell) that has a
LOWER concentration of solute
HYPERTONIC – the area that
has a HIGHER concentration of
solute
Tissue
________________________
– a group of cells that are
similar and work together
Ex. – epithelial cells make up skin; nerve cells make up
nervous tissue; muscle cells make up muscle tissue
Organ
________________________
– a group of different tissues
that work together to perform specific functions
Ex. – heart, muscle, brain
Organ System
________________________
– a group of organs that
work together to perform specific connected tasks
Ex. Skeletal, circulatory, muscular, male repro, female
repro, integumentary, nervous, endocrine, excretory,
digestive, immune
Organism
________________________
– a group of organ systems
Stoma - openings on
the bottoms of leaves
through which gases
enter or exit
fermentation
Anaerobic process
of breaking down
food into CO2
What type of
fermentation occurs
in human muscles?
Lactic acid
fermentation
What type of
fermentation
produces yogurt?
Lactic acid
What type of
fermentation
produces bread?
alcohol
Where is potential
energy stored?
In chemical bon
of ATP and foo
The kind of energy
that is energy in
motion
Kinetic energy
What does ATP stand
for?
adenosine
tri-phosphate
Mitosis
• The part of a cell’s life cycle when
the cell divides it nuclear contents
into 2 nuclei which are identical
•Mitosis consists of 4 steps:
•Prophase
•Metaphase
•Anaphase
•Telophase
Cytokinesis
• The part of a cell’s life cycle when the
cytoplasm divides into 2 cells which are
identical
DIPLOID
• Body cells are all diploid
• They contain chromosomes in PAIRS
HAPLOID
• A haploid cell has ½ the normal number of
chromosomes
• Only contains ONE chromosome from each
pair
• Sex cells = egg and sperm
Somatic cell = body cell
gamete = sex cells
Meiosis
Formation of 4 haploid/sex cells
Gregor Mendel




Lived from July 20, 1822 – January 6, 1884)
Austrian monk
Worked in monastery garden
Used pea plants to show that the inheritance
of traits follows particular laws, which were
later named after him
Trait – a characteristic of an organism
Heredity – the study of how traits are
passed from parents to offspring
True breeding plants – have offspring that
always show the same form of the trait
Cross fertilization – a process in which
one plant fertilizes the egg in a flower of a
different plant
Pollen – tiny grains containing sperm; the
male plant gamete
Hybrids – the offspring of two different
true breeding plants
Monohybrid cross – a cross between
two organisms that differ in only one
trait
Dihybrid cross – a cross between two
organisms that differ in 2 traits
Mendel’s conclusions:
Gene – the factor that controls traits
Allele – the possibilities of a gene
(e.g. A or a)
Simple dominance – one allele is
dominant to a recessive allele
Mendel Vocabulary
Dominant – the allele that masks any other allele
when there are 2 alleles present (A in Aa)
(symbolized by the first letter in the dominant trait’s
name, always capital)
Recessive – the allele that is masked by another allele
(a in Aa) (symbolized by the first letter in the
dominant trait’s name, always lower case)
More Mendel Vocabulary
Homozygous – having two identical alleles for a trait (AA
or aa) (Mendel called this “true-breeding”)
Homozygous dominant – having two dominant alleles for a
trait (AA) (Mendel called this “true breeding dominant”)
Homozygous recessive – having two recessive alleles for a
trait (aa) (Mendel called this “true breeding recessive”)
Heterozygous – having two different alleles for a trait (Aa)
Phenotype – the visible traits
of an organism (e.g. long or
short)
Genotype – the alleles that an
organism carries (e.g. Aa or
AA or aa)
Punnett square – a model used to
represent crosses between
organisms
Example: What are the possible offspring of a cross
between a homozygous dominant green plant (GG) and a
homozygous recessive green plant (gg)?
Frederick Griffith
• 1928
• How do bacteria make
people sick?
• Injected mice with
bacteria. Mice died.
• Injected mice with
heat-killed bacteria.
Mice lived.
• Conclusion:
– Something in cells
causes disease.
– He called it the
‘transforming principle’
Oswald Avery
• 1944
• Identified all the molecules in
the bacteria that caused
disease in Griffith’s
experiments
• Injected mice with bacteria –
each group of mice received
different molecules from the
original bacteria.
• The mice that received the
DNA died. The mice that
received the other molecules
didn’t die.
• Conclusion:
– DNA stores and transmits the
information in a cell.
1950s
Rosalind Franklin and Maurice Wilkins took xray photographs of DNA
1953
James Watson and Francis Crick determine that
DNA is a double helix
The Sides of the Ladder are made
up of millions of alternating sugars
and phosphates.
• The sugar is named
deoxyribose.
• The two sides of the
ladder are held together
by rungs attached to the
sugars.
Rungs of ladder –
each rung contains 2 bases
•Bases contain nitrogen so we call
them nitrogenous bases
• The 2 bases of each rung are
connected by a hydrogen bond
•There are 4 bases to choose from:
Adenine
Thymine
Guanine
Cytosine
Complementary Base Pairing
Adenine always pairs with thymine.
Guanine always pairs with cytosine.
Thymine always pairs with adenine.
Cytosine always pairs with guanine.
So, if you know ONE side of the
DNA, you should be able to figure
out the other!
What is a nucleotide?
A nucleotide is a small piece of DNA
which contains:
•1 base
•1 sugar
•1 phosphate
Lots of nucleotides link up together to
make a big DNA molecule.
DNA Replication
• Process in which DNA makes an exact copy of
itself
Interphase before Mitosis
• Occurs during __________________________
Steps of DNA
Replication
1. When it is time to
replicate, the DNA
unzips (at the hydrogen
bonds)
2. New complementary
nucleotides move in to
match BOTH halves of
the DNA and form
hydrogen bonds with the
old nucleotides.
3. Product: 2 identical DNA
molecules!
How genes work
Genes carry the instructions for making proteins.
Whenever a cell needs a particular protein, that gene
is triggered to make a protein.
There are 2 steps to making a protein:
1.
Transcription – the gene for the protein that
you want is copied in the nucleus so that the
original DNA never has to leave the nucleus.
The copy goes to the ribosome.
2.
Translation – the copy of the gene is used
by the ribosome to make a protein
Codon = 3 letters on mRNA
Anticodon = 3 complementary
letters on tRNA (transfer RNA)
The anticodon on tRNA
matches up with the codon
on mRNA and brings with
it the amino acid that the
codon codes for!
Peptide Bond = bond that
connects 2 amino acids
• As the tRNA’s bring amino acids to the
ribosome, the amino acids connect to each
other with peptide bonds.
• Many amino acids connected together
makes a protein.
Mutations
• Mistakes in the sequence of DNA
• 3 types of mutations:
– Substitution – one base is changed
– Deletion – one base is left out
– Insertion – an extra base is added
Taxonomy
• The science of classifying
organisms and assigning
each organism a name
Aristotle
•4
th
century BC
•Greek
•2 groups – plants and
animals
•He divided the
category of animals
according to how they
moved (swimming,
walking, flying)
Carolus Linnaeus
•18th century
•Swedish
•2 groups – plants and
animals
•he divided the animal
group according to
similarities in form (e.g.
bats with mammals, not
birds)
•Binomial nomenclature
Binomial Nomenclature
• Developed by Carolus Linnaeus
• Each species is assigned a two part
scientific name which is always written in
italics. The 1st word is always capitalized,
the 2nd word is always lower case.
• Ex: Homo sapiens and Homo neanderthalis
Genus – group of
closely related
species
Species – group of similar
organisms that can breed
and produce fertile
offspring
Eubacteria and Archaea
• Bacteria
• unicelluluar
• may be
heterotrophic or
autotrophic
• Do not have
subcellular
organelles
Protists
• Unicellular
• Autotrophic and
heterotrophic
• Euglena
• Paramecium
• Amoeba
• Have subcellular
organelles
Fungi
• Yeast
(unicellular)
• Mold (multi)
• Mildew (multi)
• Mushrooms
(multi)
• heterotrophic
Plantae
• Algae
• Ferns
• Flowering
Plants
• Autotrophic
• Multicellular
Animalia
• Multicelluluar
• heterotrophic