Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Biology 121 Final Exam > Exam 2 Content > Flashcards

Exam 2 Content Flashcards

You may prefer our related Brainscape-certified flashcards:
AP® Biology flashcards Biology 101 flashcards
1
Q

Who is Gregor Mendel?

A

Austrian monk who lived in the 1800s
The first person to come up with a quantitative way to deal with inheritance and come up with a mechanism of how it worked

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what are alleles?

A

Alternative forms of genes
Different alleles available for each heritable characteristic

For each inherited characteristic a diploid organism has 2 alleles at each locus/each gene (one allele from each parent)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is a locus?

A

Gene for a trait exists in a location (on homologous chromosomes)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is the difference between homozygous and heterozygous chromosomes?

A

If the alleles are identical they are homozygous and true breeding(RR or rr)
If the alleles are different they are heterozygous (Rr)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is a phenotype?

A

the physical appearance of an organism, more specifically what traits are expressed in an organism

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what is a genotype?

A

the actual genetic makeup of an organism

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what is incomplete dominance?

A

F1 and F2 have a intermediate between (1:2:1 phenotypic and genotypic ratio)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what is Epistasis?

A

One gene masks the effect of the other
1 gene has veto power
Biochemically one gene is further in the pathway than the other
Example: aa is epistatic over the b gene

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what is Polygenic?

A

Multiple genes interacting
Human height
5 - 10 loci contribute to phenotype
Melanin is determined by 3 genes
Race is social construct not biological

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what is Pleiotropy?

A

Single gene has many phenotypic characters
Sickle-cell anemia which leads to a complex set of outcomes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what is Penetrance?

A

Percent of individuals carrying the gene and showing the expected phenotype
Retinoblation (incomplete penetrance)
Not everyone that has the dominant allele has that problem

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what is Expressivity?

A

Degree of which a gene is expressed
Mild, moderate, or severe

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what are the 2 single gene defects?

A
  1. Autosomal (22 autosomes)
    Can be dominant or recessive
  2. Sex-linked (1 per sex chromosome)
    Can be dominant or recessive
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

how to read a human pedigree?

A

Circles = females
Squares = male
Filled in = phenotype of interest is present
Open = disease is not present

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what are the characteristics of autosomal recessive diseases?

A

Parents are generally normal (non-expressive)
Siblings are the only affect relatives
Males and females have it at equal proportion
Parents are consanguineous
- Same blood line

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

what are the characteristics of Autosomal Dominant diseases?

A

You only need one bad allele

The affected individual will have ½ normal and ½ affected
Normal children of affected individuals will have normal kids
Males and females are affected in the same proportion
Each sex is equally likely to transmit it

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What are sex-linked diseases?

A

Usually X linked
Females are homogenetic sex (XX)
Males are the heterogenetic sex (XY)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

what are the characteristics of sex-linked diseases?

A

Higher in males than females
Phenotype is never transmitted from father to son

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

what is Eugenics?

A

Find an undesirable trait and eliminate them
Genetically modified baby
Screen eggs ahead of time

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

what did Chargaff discover?

A

Found A=T and C=G

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

what did Watson and Crick discover?

A

Proposed double-stranded helix
3 billion base pairs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

what did Meselson and Stahl discover?

A

15N (heavy) and switch to 14N (light)
Conservative ~ original is preserved and new ones are made
Dispersive ~ mix of old and new DNA
Semiconservative ~ old DNA acts as a template
1 division by centrofusion
Has 1 strand of 15N and 1 strand of 14N

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

what occurs in Replication?

A

1 strand of DNA is the template strand
Unzips DNA
Uses DNA Helicase powered by ATP
Nucleotides are linked together by covalent bonds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

what is Fidelity?

A

The chance on miscopied DNA for base pairs is 1 in 10^6 bp
Proof-reading enzyme
Repair of mismatch DNA enzyme
Lowers overall rate to 10^10 bp

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

what is Central Dogma?

A

Information from DNA is utilized to make proteins
DNA is transcribed to mRNA and then translated into proteins
- DNA is the blueprint for genes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

what is transcription?

A

The DNA template is recorded
3 different steps

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

what is translation?

A

the process by which a cell makes proteins using the genetic information carried in messenger RNA (mRNA). The mRNA is made by copying DNA, and the information it carries tells the cell how to link amino acids together to form proteins.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

what is the process of translation?

A

mRNA → amino acids → proteins
20 amino acids
Use codons (3 nucleotides) which equal 64 combinations
Genetic code is degenerate
More than one set of codons code for genes
Takes place in the ribosomes
Scaffolding
mRNA is read (start codon AUG)
tRNA has an anticodon that is complementary the codon
Then added to the polypeptide chains
Creates amino acids
Stop codons are UAA, UAG, UGA
Once it hits this, polypeptides are released

29
Q

what is a point mutation?

A

Replace one nucleotide with another

30
Q

what is a silent mutation?

A

No change in protein
Codes of the same amino acid

31
Q

what is a missense mutation?

A

Results in an amino acid substitution
Sometimes no problem but other times it makes a big difference (sickle cell animea)
Get valine instead of glutamic acid

32
Q

what is a nonsense mutation?

A

Substitutes a stop codon for an amino acid
Makes the protein shorter so it probably doesn’t work

33
Q

what is a Frameshift mutation?

A

Add or delete a nucleotide
More disastrous than point mutations
mRNA is read as a series of nucleotide codons so the reading frame is altered from that point on

34
Q

what is a Spontaneous mutation?

A

Just happens are a low rate

35
Q

what are mutagens?

A

Chemical or physical traits that disrupt/change your DNA to cause it mutate

36
Q

what are Transposable Elements?

A

they make a mess of genes

37
Q

what are SNPs?

A

Single nucleotide polymorphisms
Places where minor changes in base pair take place
High in some populations but smaller in others
Useful in ancestry study
In Iceland decode is a company that has health, genealogy, and DNA sequence from Iceland’s population
All related to each other (relatively)

38
Q

what is Natural selection?

A

Process that descents different survival and reproduction of individuals which have different heritable traits

39
Q

who discovered the Adaptation Theory?

A

Lamark (1809)

40
Q

what is the adaption theory?

A

Use and disuse of parts
Orgaisms have a built in drive towards perfection
Inheritance of acquired characteristics
Modification during lifetime passed down during generation

41
Q

what does natural selection act upon?

A

Different phenotypes → different genotypes
Natural selection acts on phenotypes

42
Q

what is the cause of natural selection?

A

Cause of natural selection is abiotic and biotic environment
Not on genotype that is good in all situation
Depends on current environment
Benefits individuals not groups
Not for good of species but what is best for the individuals and its genes
Natural selection sifts varates from less successful to more successful
Selection can change gene frequency (phenotypes)

43
Q

what is a gene pool?

A

Total of all genes in all individuals in a population

44
Q

what is evolution?

A

Change in genetic makeup in a population overtime
All forms of life are descended with modifications from ancestral species
Due to natural selection (a mechanism)

45
Q

what is Rifampin?

A

Antibiotic that targets a protein in the bacteria (RNA polymerase) then kills the bacteria

46
Q

what is the Hardy-Weinberg Law?

A

In a sexually reproducing population single generation of random mating results in (produces) stable/constant frequency of alleles and phenotypes

47
Q

what are the 5 requirements of Hardy-Weinberg?

A
  1. Large population
  2. No mutations
  3. No migration
  4. Random mating
  5. All genotypes have equal reproductive success
    • No natural selection
48
Q

what is Stabilizing Selection?

A

Intermediate phenotype is favored over the extreme
Increase the frequency of the average phenotype
Reduce genetic variation

49
Q

what is directional selection?

A

One extreme phenotype is favored over the other
Shifts distribution of offspring in one direction

50
Q

what is disruptive selection?

A

Both extremes phenotypes are favored over the intermediate

51
Q

what is relative fitness?

A

Survivorship/reproduction of a phenotype compared to the best one in the environment
- Mainly uses survivorship

52
Q

What are the characteristics of sickle cell anemia?

A
  • Autosomal recessive disease
  • SIngle base pair change in hemoglobin (4 chains) causing a change in shape in red blood cells
  • Missense mutation
53
Q

what is Non-Random Mating?

A

Organism chooses its type based on ideal phenotype

54
Q

what is Assortative mating?

A

Mating with similar phenotypes
Social, political, religious constraints, which leads to reproductive isolation
Leads to recessive genetic disease clustered in a group

55
Q

what is inbreeding?

A

Mating with individuals that have shared genes which are identical by descent

56
Q

what is Migration?

A

Gene flow increases or decrease genetic variation
Can bring in novel alleles to population (increase genetic variation)
Homogenize populations (reduces genetic variation)
Gene flow between populations makes them similar

57
Q

what is genetic drift?

A

Change in allele frequency due to chance
Relative fitness of the allele does not matter
Important in small populations
Random fluctuations in allele frequency can lead to loss of allele by chance

58
Q

what is the Founder Effect?

A

the reduction in genomic variability that occurs when a small group of individuals becomes separated from a larger population.

59
Q

what can cause increased genetic variation?

A

Sexual reproduction can increase genetic varaition but cannot change allele frequency
Gene flow can increase genetic variation by immigration

60
Q

what can cause decreasing genetic variation?

A
  • Stability selection
  • Directional selection
  • Can remove an allele from the population (fixation)
  • Genetic Drift
    - Lose alleles
  • Inbreeding
    - Reduce heterozygosity but not change allele frequency
  • Gene flow
    - Can homogenize populations which prevent new combinations
61
Q

what is Speciation?

A

Process of splitting one species into several

62
Q

what is Allopatric Speciation?

A

When a population forms a new species while geographically separated from the parent population
Example: Mountain, ocean, pond, roads, etc.

63
Q

what is Prezygotic isolation?

A

Reduces the probability of a zygote forming
Do not cost very much (avoiding species)

64
Q

what are the 5 types of Prezygotic isolation?

A
  1. Habitat Isolation:
    Leopard frog
  2. Temporal Isolation:
    Mate/flower at different times
  3. Behavioral Isolation:
    Little sex attraction
    Sometimes mediated by chemicals (pheromones)
  4. Mechanical Isolation:
    Different mating parts
  5. Gametic Isolation:
    Gametes fail to attract each other
65
Q

what is Postzygotic isolation?

A

Reduces performance of zygote
Cost valuable resources (dooming the carrier of genes)

66
Q

what are the 3 types of Postzygotic isolation?

A
  1. Developmental Isolation
    The embryo does not develop
  2. Hybrid Inviability
    Hybrid adults are weak and die before they can reproduce
    No gene flow
  3. Hybrid Sterility
    Hybrid does not produce functional gametes
    Mules (horse x donkey)
    Liger (lions x tigers)
67
Q

what is Adaptive Radiation?

A

emergence of (numerous) new species from a common ancestor usually introduced to a new environment

68
Q

what is the difference between allopatric and sympatric speciation?

A

In allopatric speciation, groups from an ancestral population evolve into separate species due to a period of geographical separation. In sympatric speciation, groups from the same ancestral population evolve into separate species without any geographical separation.

69
Q

what is the Hybrid Zone?

A

Well-defined geographic area where hybridization occurs

Biology 121 Final Exam (3 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions