Download Notes Summary for Biology Keystone

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A.1 Basic Biological Principles
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Characteristics of all living organisms:
– are made of cells
– obtain and use energy
– grow and develop
– reproduce on their own
– respond to their environment
– adapt to their environment
All cells have ribosomes, cytoplasm, plasma membranes, and genetic material (DNA)
All life is divided into two groups of cells – prokaryotes and eukaryotes
Prokaryotes
Example: bacteria
No nucleus
No membrane-bound organelles
On earth for 3.5 billion years
Typically smaller cells
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Eukaryotes
Example: animals, fungi, protists, and plants
Have nucleus
Have membrane-bound organelles (like
mitochondria, rough ER, and Golgi apparatus)
On earth for 1 billion years
Typically larger cells
Important Organelles and their functions:
– Ribosome – makes proteins
– Rough ER – transports proteins
– Golgi Apparatus – modifies, processes, and packages proteins into vesicles (sacs) for delivery
– Nucleus – contains genetic material (DNA)
– Mitochondria – makes energy (ATP); does respiration
– Chloroplast – makes food (sugar); does photosynthesis
– Lysosome – breaks down materials
Organizational levels from smallest to largest – organelles, cells, tissues, organs, organ systems,
organism
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A.2 The Chemical Basis for Life
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Water important to life on earth
– Water molecules stick to each other (cohesion) and other molecules (adhesion)
– Water changes its temperature slowly (has high specific heat)
– Ice is less dense than water
– Water is the universal solvent
Carbon makes 4 covalent bonds so a wide variety of molecules are possible.
Small monomers (building blocks) are joined together to make large polymers.
Large molecules = macromolecules: Carbohydrates, lipids, proteins, and nucleic acids
Enzymes are proteins that act as catalysts. Catalysts speed up chemical reactions. They do this by
lowering activation energy. Activation energy is the energy required to start a chemical reaction.
Enzymes work on molecules called substrates. Substrates can have something added or be broken
down by enzymes. Example: The enzyme lactase breaks down the sugar called lactose.
The temperature, pH, and concentration levels of substrate and enzyme can all affect enzyme activity.
Each enzyme has a particular pH and temperature range where they work best (optimal). Example:
Pepsin (an enzyme in your stomach) works best at an acidic pH of 2. Most of your enzymes work best at
98.6°F. High temperature or high or low pH changes the shape of an enzyme which means it cannot do
its job.
Characteristics
Monomer
(building blocks)
Carbohydrates
Proteins
Nucleic acids
Lipids
sugar
amino acids
nucleotides
none
Uses
provide energy
building materials,
fight disease,
transport materials
genetic
material
provide insulation and
protection, storage of
energy
hemoglobin
DNA, RNA, ATP
fats, fatty acids
Examples
glucose, starch,
cellulose
glucose
amino acid
fatty acid
Important
Structures
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A.3 Bioenergetics
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Photosynthesis: sunlight + 6H2O + 6CO2
C6H12O6 + 6O2
– Converts light energy into chemical energy (sugar)
– Uses sunlight, H2O, and CO2
– Makes glucose (sugar) and O2
– Occurs in chloroplasts
– Plants, algae, and some bacteria do photosynthesis
Cellular Respiration: C6H12O2 + 6O2
6H2O + 6CO2 + ATP (energy)
– Converts chemical energy (from glucose) into a different chemical energy (ATP)
– Uses glucose (sugar) and O2
– Makes CO2, H2O, and energy (ATP)
– Occurs in mitochondria
– All living things do some type of respiration because all living things need to make energy.
ATP is adenosine triphosphate (has 3 phosphates). This is the major energy source for your cells.
– ATP can chop off a phosphate, which releases energy and makes ADP.
ATP
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ADP + Phosphate + Energy
ADP is adenosine diphosphate (has 2 phosphates).
– ADP can add a phosphate, which requires energy and makes ATP.
ADP + Phosphate + Energy
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ATP
ATP is like a fully charge battery. ADP is like a partially charge battery.
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A.4 Homeostasis and Transport
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Plasma membrane is the protective barrier around all cells.
– Plasma membrane is made primarily of phospholipids. It also has
proteins.
– Phospholipids have hydrophobic phosphates and hydrophilic fatty
acids.
Types of transport
– Passive transport – no energy required
 Diffusion – moves molecules from high to low concentration
 Molecules diffuse based on size and temperature. In this diagram the larger
molecules cannot diffuse, but the smaller ones diffuse out of the bag.
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Osmosis – moves water from high to low concentration
 Water moving into or out of a cell can cause the cell to burst, swell, or shrivel.
 Facilitated diffusion – moves materials through a protein from high to low
concentration
– Active Transport – requires energy
 Active transport moves molecules from low to high concentration
 Protein pumps help to move materials via active transport.
– Miscellaneous
 Endocytosis – membrane wraps around and engulfs materials and puts them in a vesicle
 Exocytosis – vesicles on inside of cell fuse with membrane and materials are released to
outside
Membrane-bound organelles help transport materials inside cells.
o Rough Endoplamsic Reticulum (rough ER) transports proteins
o Golgi apparatus packages materials in vesicles (sacs) to be delivered all over cell (like the post
office).
Organisms must regulate different things in their bodies like temperature, pH, water, oxygen to
maintain homeostasis. Homeostasis means keeping a stable, internal environment.
o Examples:
 Freshwater fish gain water by osmosis so they must produce watery urine to get rid oe
excess.
 Saltwater fish lose water by osmosis so they must produce concentrated urine to get rid
of salt (saving water).
 People sweat and dogs pant to reduce body temperature.
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B.1 Cell Growth and Reproduction
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Cells divide to make more cells.
Cell Cycle:
o Interphase
 G1 – cells grows
 S – copies DNA
 G2 – cell continues to grow
o Nuclear Division – either mitosis or meiosis
o Cytokinesis – finish cell division; pinching in of cell membrane (cleavage)
Mitosis
– Makes 2 body cells (diploid)
– Chromosome number stays the same (cloning)
– Humans make 2 cells with 46 chromosomes.
Meiosis
– Makes 4 sex cells (gametes – sperm or eggs - haploid)
– Chromosome number is halved
– Humans make sex cells with 23 chromosomes.
DNA is a double helix made of sugar, phosphate, and bases.
The order of the bases (A, T, C, and G) makes the genetic code and makes different genes.
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DNA is copied (replicated) before a cell divides (mitosis or meiosis).
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Your DNA is the molecule that makes up chromosomes. One strand of DNA is a chromosome. Each
chromosome has many genes (sections of the DNA that make a protein). A gene can come in different
forms or alleles (ex. recessive and dominant).
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B.2 Genetics
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A gene makes a protein through transcription and translation.
– DNA:
TAC AAA TTC ATT
– mRNA:
AUG UUU AAG UAA
– Protein:
met – phe –lys stop
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Transcription – DNA is used to make mRNA. Occurs in the nucleus.
Translation – mRNA is used to make protein (amino acids that are linked together). Occurs at a
ribosome.
Mutations – change in the sequence of bases (A,T,C,Gs)
– Gene mutations
 Point – one base changed (ex. an A is changed to a C)
 Frameshift mutations – inserting or deleting a base (changes the reading frame)
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Chromosomal mutations
 Deletion – big part of chromosome sequence deleted
 Duplication – big part of chromosome sequence repeated
 Inversion- part of chromosome sequence inverted (reversed)
 Translocation – part of one chromosome is moved to another chromosome
 Nondisjunction – during meiosis when a sex cell ends up with the wrong number of
chromosomes
Mutations may change a protein, but do not have to change it. A mutation can be silent (no change),
change an amino acid, or cause a premature stop codon. A mutation may have no effect or may be
either harmful or beneficial.
Genetic engineering - manipulation of genes
o Genetically modified organisms - giving rice the gene to make beta carotene
o Cloning – many animals have been cloned starting with Dolly the sheep
o Gene therapy – trying to put a gene in a sick person to make them better
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Life of a protein
o Nucleus holds DNA which provides instructions to make proteins.
o Ribosomes make proteins.
o Proteins often move into the rough ER. In the rough ER proteins may be modified and are
transported.
o These proteins often go to the Golgi apparatus in vesicles (sacs). In the Golgi proteins are
modified, sorted, and packaged in vesicles.
o These vesicles take proteins to their destination somewhere in the cell or to the plasma
membrane.
Genetic Problems “Cheat Sheet”
“Normal Problems”
Incomplete Dominance
Co-dominance
Sex-linked
Dominant or Recessive
Homo = BB (black)
Homo = BB (black)
XX = girls
B = dominant
Homo = WW (white)
Homo = WW (white)
XY = boys
b = recessive
Hetero = BW (gray)
Hetero = BW (black and
white)
Letters for genes only go
on X’s (not Y’s).
Blood Type
Pedigrees
Vocabulary
AA and Ao = Type A
homozygous = same alleles (BB or bb)
BB and Bo = Type B
heterozygous = different alleles (Bb)
oo = Type O
carrier - heterozygous
Shaded = recessive
Aa, AA, or A? for each
phenotype = physical trait (ex. brown eyes or blue
eyes)
genotype = type of genes (ex. BB, Bb, or bb)
Normal Problem (Brown eyes are dominant to blue. Cross two heterozygous people.)
B
b
B BB
Bb
b Bb
bb
3/4 brown eyes
1/4 blue eyes
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Incomplete dominance (BB = black, WW = white, and BW = gray - Cross a black cat with a white cat.)
B
W BW
W BW
B
BW
BW
4/4 gray
Codominance (BB = black, WW = white, and BW = black and white spotted - Cross a black cat with a white cat.)
B
W BW
W BW
B
BW
BW
4/4 black and white spotted
Blood Type (Cross a homozygous type A with a heterozygous type B.)
A
A
B AB
AB
o Ao
Ao
2/2 Type AB
2/2 Type A
Pedigrees (Shaded people have recessive trait – albino).
Aa
Aa
aa
A?
Sex-linked (Hemophilia is sex-linked and recessive while normal blood cells are dominant. Cross a carrier woman
with a normal male.)
XH
Xh
XH XH XH XH Xh
Y XHY
XhY
2/4 normal females
1/4 normal male
1/4 hemophilia male
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B.3 Theory of Evolution
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Evidence of evolution
– Fossils – shows extinct organisms existed
– Biochemistry – comparing DNA and protein sequences (Chimpanzees and human have more
similar DNA than frogs and humans)
– Comparative anatomy – comparing physical body structures (forelimb structures of human can
cat are more similar than whale and human)
– Comparative embryology – comparing embryos (embryos of pig and human are more similar
than embryos of frogs and humans)
– Direct Observation – witness changes in populations over time (increasing number of bacteria
becoming resistant to antibiotics)
 Natural selection is when the best adapted individuals survive and reproduce. For example, imagine a
grassy environment where there are tan and green snakes. The green snakes are more common. Over
time the land dries up and the grass dies leaving a more desert-like area. This makes the tan snakes
more common than the green. The tan snakes were able to camouflage themselves in the “desert-like”
environment. The tan snakes were better able to survive and reproduce compared to the green. The
environment “selected” the tan snake.
– The environment did NOT change a green snake into a tan snake. The environment can only
select for or against a trait that already existed in the population.
 Adaptation – a trait that has evolved through natural selection and is a benefit to the organism
– Structural – physical part (ex. pointy teeth for eating meat)
– Physiological – chemical (ex. poison to kill prey)
– Behavioral – an action (ex. mating dance to attract mate)
 Speciation – the formation of a new species
– Isolation mechanisms – keep two groups apart and allow for forming two species
 Geographic – a geologic event separates two groups (Ex. Grand Canyon squirrels)
 Temporal – timing differences (species that mate at different times of year)
 Behavioral – different behaviors (birds that have different mating dances)
 Genetic – genetic differences prevent fertile offspring (horses and donkeys make sterile
mules)
 Genetic drift – rapid gene frequency changes that occur by change in small, isolated populations
 Small populations do not typically have the diversity that larger populations have.
 Evolution is change in populations over many generations. Gene frequencies change in order for
evolution to occur.
 Scientific Terms
– Hypothesis – an educated guess
– Inference – a conclusion based on data
– Law – generalizes numerous observations; no exceptions have been found
– Theory – explanation based on observation, empirical data
– Fact – a truth known by observation or experience
– Observation – something that can be seen/measured
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B.4 Ecology
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Levels of ecological organization from smallest to largest: species, population, communities, ecosystem,
biome, biosphere
Abiotic - nonliving (rocks, air, water etc.)
Biotic – living (plants, fungi, animals etc.)
Food Webs
– Producers make food (photosynthesis)
– First consumers eat producers
– Second consumers eat first consumers
– Third consumers eat second consumers
The amount of available energy decreases as you move up a food chain. More available energy is in the
producers compared to the consumers. Energy is lost through metabolism, heat, and feces.
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Succession – how living things change in an area after a disturbance; typically small plants grow first
followed by animals and then larger plants; first species in an area are pioneer species (ex. lichens)
Limiting factors – decrease the number of individuals in a population (ex. lack of food, contagious
diseases, lack of habitat, predators etc.)
– Could lead to the extinction of a species
– May cause a population to reach it’s carrying capacity (maximum number of individuals the
environment can support)
Interactions
– Competition – fighting over resources (like mates, territory)
– Symbiosis – a very close relationship where on individual is living in or on another
 Mutualism – benefits both
 Commensalism – benefits one and does nothing to the other
 Parasitism – benefits one and harms the other
– Predator prey relationship
 If predators increase then prey decreases (they are eaten).
 If predators decrease then prey increases (not as many eaten).
 If prey increases then predators increase (plenty to eat).
 If prey decreases then predators decrease (not enough to eat).
Nitrogen cycle
– Plants and animals cannot use nitrogen gas. Animals eat to get nitrogen. Plants need bacteria.
 Bacteria fix nitrogen so that plants can use it. These bacteria can live in the soil; some
bacteria can live in the roots of plants called legumes (soy beans).
– Decomposition puts nitrogen back into the soil.
– Some bacteria can convert nitrates back into nitrogen gas.
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