Bio Finals Sem 2

Ch 15-16, Ch 3-6, Ch 7 (blood typing, sex-linked genes, CRISPR, ecology) | *NOT on flashcards: Pedigrees

Ch 15

Ch 15

How many chromosomes in a human body (somatic) cell?

46

How many chromosomes in a human sex cell (gamete)?

23

What are sex chromosomes in humans?

X and Y, the 23rd pair

What are autosomes?

The non-sex chromosomes (everything except 23rd pair)

All eggs carry an __ chromosome, half of all sperms carry an __, and the other half carry an __ chromosome

Eggs: X

Sperm: Equal probability of X or Y

What happens when you mix two different blood types?

Blood coagulates (patient dies)

What are the blood types (antigens)?

A: contain only A antigen

B: contain only B antigen

AB: contain both A & B antigens

O: contain neither A or B antigents

What are Rh Groups? Who’s dominant?

Determined by a single 2-allele gene. Rh+ allele is dominant.

Rh+ Rh±: positive+ blood with Rhesus antigen

Rh- Rh-: negative- blood without Rhesus antigen

Genotypes of A, B, AB, and O bloods.

A: I^AI^A, I^A i

B: I^BI^B, I^B i

AB: I^AI^B

O: ii

i is recessive to the others, I^A and I^B are codominant with each other

Who can donate blood to who? Who can receive blood from who?

A: donate (A, AB), receive (A, O)

B: donate (B, AB), receive (B, O)

AB: donate (AB), receive (A, B, O)

O: donate (A, B, AB), receive (O)

+: donate (+), receive (+, -)

-: donate (-, +), receive (-)

What is a karyotype?

A person’s chromosomes, sorted and labeled by pair #

What is amniocentesis?

taking amniotic fluid from the uterus to determine baby’s karyotype

Describe nondisjunction.

Homologous chromosomes fail to separate during meiosis, so they’re distributed unevenly among the 4 haploid daughter cells. When one matures, it may have Klinefelter’s/Turner’s/Down (an uneven number of chromosomes).

Ch 16

Ch 16

Inbreeding (pros & cons, plus example)

Continued breeding of individuals with similar characteristics.

Pro: certain good traits are preserved

Con: certain recessive alleles can combine

Ex: Habsburg jaw in Spanish royalty

What can cause mutations? (how do breeders induce them?)

Chemical/radiation exposure.

How can polyploidy be induced?

With drugs that prevent chromosomal separation during meiosis (nondisjunction!)

How do animals vs. plants react to polyploidy?

Animals: Usually fatal

Plants: Grow larger and stronger than diploid version; can become new species

What are plasmids?

Short circular piece of DNA found in bacteria

What are restriction enzymes?

Proteins naturally produced by bacteria to ward off viral infections, that cut the viral DNA at precise locations

What is gel electrophoresis?

Process of size-sorting DNA fragments by running electricity through gel. The smallest fragments travel the farthest from the wells.

Sequence this (gel electro results)

ATG TCC GAT

For the polymerase to work in the high temperatures used in PCR, where did its bacteria come from?

Hot springs in Yellowstone

Recombinant vs. transgenic

Recombinant: The DNA altered

Transgenic: The organism with altered DNA

Types of stem cells. (What do they become?)

• Totipotent: become ANY body cell (placenta + embryo)

• Pluripotent: become MOST body cells (embryo)

• Multipotent: LIMITED potential to differentiate into many body cells (adult)

How can stem cells be used after you get them from the donor? What are the controversies?

• Can repair damage from heart attacks, strokes, spinal cord injuries

  • harvested from bone marrow and cultured

  • injected into damaged heart portion

  • would naturally differentiate into heart cells

Controversy:

• Adult multipotent cells come from willing donors, but

• harvesting embryonic toti/pluripotent cells destroys embryo

Ch 17

Ch 17

What is evolution?

Organisms changing over time

What is a theory?

Well suported & testable explanation of natural phenomena

What did Darwin observe about organisms across Galapagos islands? (give example)

They were different everywhere. (ex: tortoise shell shapes & finch beak sizes)

What was the prevailaing belief about Earth and its organisms in the 1700s?

Fixed World View - Earth and all its forms of life have only existed and remained unchanged for a few thousand years

What discovery challenged that view?

Fossils

• some looked like modern organisms

• others looked completely different

• many had died out

Organism losing its disused structures

Whales have lost their “hind legs”

Why did Darwin decide to publish his theory?

Alfred Russel Wallace sent Darwin an essay about his almost identical thoughts on evolution

Adaptation noun def

Heritable trait increasing ability to survive

3 types of adaptations

1. Anatomical (physical)

2. Physiological (body functions)

3. Behavioral

What is fitness?

Organism’s ability to survive and reproduce - survival of the fittest

In what situations does natural selection occur?

- more individuals are born than can survive (struggle for existence)

- varying fitness

Artifical selection + example

Nature provided the variation, and humans selected those they found useful

Example: Selective domestic crops/animals

3 parts of Darwin’s evolution HYPOTHESIS

1. Struggle for existence

   1. members of a population compete for finite supply

2. Survival of the fittest

   1. individuals with certain inherited variation are better adapted to environment than others

3. Common ancestry

   1. living species are descended from common ancestors, with changes over time

Struggle for existence example

Male booby with brightest blue feet “wins” female mate

Survival of fittest example

Polar bears with largest claws/teeth get most prey, and survive/reproduce the most

What is biogeography?

Study of where organisms and their ancestors lived

Evidence of evolution

• biogeography

• fossils

(this is also evidence for plate tectonics)

What are homologous structures?

Similar structures shared between related species, inherited from common ancestors

Vestigial organs

Organ with no useful function in an organism

Darwin’s hypothesis of how different finches came to be (and what assumptions did he make?)

• common ancestors

• 1 finch arrived in Galapagos, evolving into 13

assumptions:

• must be enough heritable variation in beak shape to produce “raw material for natural selection”

• variation in beak shape must create differences in fitness

What happened when Peter & Rosemary Grant tested these Darwin’s assumptions?

• Provided concrete evidence for Darwin’s theories

• Found a great variation of heritable traits

• Individual birds with different sized beaks had different chances of survival during a drought

• Likely led to speciation

• evolution can happen quickly

Ch 18

Ch 18

What is a gene pool?

Consists of all genes, including different alleles, in a population

What is allele frequency/relative frequency? (how do you express it? is it related to dominant alleles)

Number of times an allele appears in a gene pool compared to others - a percent

doesn’t have to be expressed, and does not relate to if the allele is dominant

3 sources of genetic variation

1. Mutation

   1. heritable change in DNA

2. Crossing over

   1. can create 8.4 million combinations from 23 chromosomes

3. Lateral gene transfer

   1. transfer of genetic material to non-offspring organism

   2. some bacteria do this

How do mutations affect organisms?

Most of them have no effect

How does crossing over/gene recombination affect populations?

• creates genetic variation!

• (8.4 million combinations from 23 chromosomes)

Single-gene vs polygenic trait

Single-gene traits:

• 1 gene

Polygenic:

• multiple genes, often 2+ genes

• many possible genotypes & phenotypes

What shapes do graphs of polygenic traits make, and why?

Bell curves, because it’s less probable to get all extreme alleles of one type than a mix of different alleles

How does natural selection help resistance to occur?

1. Some bacteria, by chance, have genetic variations that let them resist an antibiotic

2. Over time the allele frequency for this allele increases

(Natural selection - by chance, one can resist it, and they survive/reproduce more often)

Natural selection’s impact on single gene traits

changes in allele frequencies → changes in phenotype frequency

natural selection’s 3 different kinds of impacts on polygenic traits (name them)

1. Directional selection

2. Stabilizing selection

3. Disruptive selection

directional stabilization

one end of bell curve is fittest, so bell curve shifts in that direction

stabilizing selection

center of bell curve is fittest, so bell curve steepens

disruptive selection

extreme ends of bell curve are fittest - graph dips in middle

Founder effect

when a small group leaves to a new isolated location and establishes that location’s gene pool

What is speciation? (have we seen it?)

species changing so dramatically they can’t mate - haven’t seen it

Why is speciation the core theory of evolution?

Creates biodiversity and variety from which more speciation can happen (evolution). Speciation drives evolution

Species (singular) - how is it different from population?

species: group of organisms who CAN mate/produce offspring

population: group of organisms who DO mate

Types of isolation (name them)

1. behavioral isolation

2. geographic isolation

3. temporal isolation

behavioral isolation & example

two populations CAN interbreed, but WON’T because of mating rituals/behavior choices

ex: Eastern and Western meadowlark sing different courtship songs

geographical isolation & example

two population CAN mate, but are separated by water, mountain, etc.

ex: Abert’s and Kaibab squirrel across Grand Canyon

temporal isolation & example

two populations CAN mate, but mate at different times of the year

ex: orchids releasing pollen only one day

Ch 19

Ch 19

What is binomial nomenclature?

genus, species (2-word naming system)

Linnaeus’s 2 kingdoms

Plantae & Animalia

Name all the current kingdoms (okay if not know completely - on cheat sheet)

Eubacteria, Archaebacteria, Protista, Fungi, Plantae, Animalia

Name all the domains (which ones have peptidoglycan?)

Eukarya: protists, fungi, plants, animals

Bacteria: eubacteria WITH peptidoglycan

Archaea: archaebacteria WITHOUT peptidoglycan

Who can purr?

House cats

Who is a carnivore?

Wolf, leopard, house cat

The tortoise’s closest relative is…

horse

Ch 20

Ch 20

Earth’s layers are… (okay if don’t know completely - on cheat sheet)

Crust

(lithosphere = crust/tectonic plates)

(asthenosphere = upper mantle/thing plates float upon)

Mantle

Outer Core

Inner Core

What are plates?

lithosphere divided into plates, carrying amounts of continental/oceanic crust, floating on asthenosphere

What drives plate tectonic movements? By how much?

convection currents within Earth - they move very slowly

weathering

breaking rocks chemically/physically into smaller pieces

erosion (by what medium?)

small pieces of rock are carried away by wanter, wind, or glaciers

deposition

small particles of sand, silt, or clay are carried by water where they settle out layers of sediments at the bottom

Weathering causes erosion causes deposition

know this

Igneous rocks

magma cools and hardens beneath the surface or after a volcanic eruption

Sedimentary rocks

sediments are compressed and cemented together into rocks

Metamorphic rocks

rocks change under extreme heat and pressure

How do fossils form?

• dead organisms are buried under layers of sediment → usually found in sedimentary rock and as marine creatures

• water seeps in, depositing minerals

Fossil quality varies (T/F)

true

What conditions are needed for fossil-ization?

Rapid burial in sediments immediately after death

types of fossils (know generally)

• skeleton

• imprint

• amber

• eggs

• poop

Fossils are usually… complete or incomplete?

incomplete

Why will the fossil record never be complete?

We will never uncover every fossil that has formed

How does relative dating work?

• put rock layers and their fossils into a time sequence, where lowest is oldest

• use index fossils as timestamps

How does direct dating (radiometric dating) work?

• measuring radioactive decay, especially carbon-14

What is half life?

The amount of time in which a sample halves

Describe the Miller-Urey experiments

• simulated early Earth’s conditions

• with hydrogen, methane, ammonia, & water for atmosphere and electricity as lightning

• Results: after several days, 21 amino acids were produced

• Helped show how organic compounds could have come from early Earth’s conditions