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MCAT BIOLOGY FLASHCARDS > MCAT BIO CH. 7 PART 1 > Flashcards

MCAT BIO CH. 7 PART 1 Flashcards

1
Q

What are allosomes?

A

Sex chromosomes

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2
Q

What are homologous chromosomes?

A

One from the mother, one from the father, two nonidentical copies of a chromosome

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3
Q

What are alleles?

A

Different versions of genes

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4
Q

What is meiosis?

A

Cell division that reduces the number of copies of each chromosome from two to one (forming haploid cells)

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5
Q

What cells in males and what cells in females undergo meiosis?

A

Spermatogonia, oogonia

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6
Q

What occurs in meiosis to share genomic content?

A

Recombination between homologous chromosomes

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7
Q

What is the product of meiosis?

A

4 haploid cells

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8
Q

What is different with prophase I in meiosis and mitosis prophase?

A

Homologous chromosomes pair with each other in synapsis

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9
Q

The paired homologous chromosomes are called….?

A

Bivalent or tetrad

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10
Q

Which meiosis state takes the longest and why?

A

Prophase I since crossing over is complex

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11
Q

What protein assist in the formation of tetrad during synapsis?

A

Protein structure called synaptonemal complex (SC)

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12
Q

How does the SC assist with homologous chromosomes, how does it start?

A

Proteins SYCP2 and SYCP3 attach to each of the two homologous chromatin structures that are to be paired

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13
Q

What is the lateral element of the SC?

A

Proteins that have attached to each of the two homologous chromatin structures

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14
Q

What occurs when the lateral elements of the SC are produced?

A

Align and attach via. centra region made of SYCP1 and other proteins

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15
Q

What do the lateral region and central regions form, based on crossing over?

A

They form the SC and work like a zipper to connect homologous chromosomes

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16
Q

What is different between metaphase I and metaphase in mitosis?

A

Tetrads are aligned at the center of the cell while in mitosis, sister chromatids are aligned

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17
Q

What is different between anaphase I and metaphase in mitosis?

A

Homologous chromosomes separate and chromatids remain together

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18
Q

What happens in telophase I?

A

Cells divides into two cells

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19
Q

What are the cells considered in telophase I, based on ploidicity?

A

Haploid; each cell has a single set of chromosomes

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20
Q

DNA replication occurs between meiosis I and II. T/F

A

False

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21
Q

The movements of chromosomes are the same in meiosis II and mitosis except that….?

A

Meiosis II has a haploid number of chromosomes mitosis has a diploid number

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22
Q

What happens at the end of telophase II?

A

Four haploid cells are produced from a. single diploid parent cell

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23
Q

What is nondijustion?

A

Homologous chromosomes or sister chromosomes failing to separate during meiosis

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24
Q

What is trisomy?

A

Gamete with two copies create a zygote with three copies of a chromosome

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25
What is monosomy?
Gamete with no copies create a zygote with one copy of a chromosome
26
What is an example of nondisjunction not being lethal in humans?
Trisomy of chromosome #21 results in Down syndrome
27
What is an example of nondisjunction in sex chromosomes being nonlethal?
Turner syndrome: organisms with 1 X and no Y
28
What are the two laws of Mendel?
1. Law of segregation | 2. Law of independent assortment
29
What is the law of segregation?
Two alleles of an individual are separated and passed on to the next generation singly
30
What is the law of independent assortment?
Alleles of one gene will separate into games independently of alleles for another gene
31
What is a test cross?
individual is crossed to another individual that has a homozygous recessive genotype
32
If the color gene and the shape gene are right next to each other on a chromosome, will they display independent assortment?
They would display an exception called linkage
33
What tool is used to visualize law of segregation and independent assortment?
Punnett square
34
What are to ways to determine the probabilities of an outcome in a cross?
1. Rule of multiplication | 2. Rule of addition
35
What is the rule of multiplication?
Probability of two independent evens occurring found by multiplying the odds of either event alone
36
What is the rule of addition?
Used to calculate the chances of either of two events happening
37
What is incomplete dominance?
Phenotype of a heterozygote is a blended mix of both alleles
38
What is codominance?
Two alleles are both expressed but not blended
39
Other than ABO, what other main antigen is used in blood typing?
Rh (rhesus) factor
40
What is the pattern of the Rh blood factor?
Rh^DRh^D or Rh^DRh^d (RRand Rr) are Rh positive and RhdRhd are Rh negative
41
What is pleiotropism?
Expression alters many different aspects of the organism's total phenotype
42
What is polygenism?
Traits influenced by many difference genes are polygenic
43
What is penetrance?
The likelihood that a person with a given genotype will express the expected phenotype
44
What type of penetrance can alleles or mutations display?
High, incomplete or low penetrance
45
What is epistasis?
Expression alleles for one gene is dependent on a different gene
46
What are recessive lethal alleles?
Mutant alleles can cause death of an organism when present in a homozygous manner
47
What is linkage?
Failure of genes to display independent assortment, located on the same chromosome
48
The frequency of recombination between two genes on a chromosome is proportional to....?
The physical distance between the genes along the linear length of DNA molecule
49
The frequency of recombinations given by....?
The number of recombinant phenotypes resulting from a cross divided by the total number of progeny
50
What is the equation of recombination frequency? (RF)
RF = # of recombinants / total # of offspring
51
What are the two types autosomal trait patterns?
1. Autosomal dominant | 2. Autosomal recessive
52
What are mitochondrial traits?
Inherited via the mitochondrial genome through the cellular material contributed by the mother
53
What does hemizygosity means and what's an example?
The individual only has one copy of the chromosome in a diploid organism; mitochondrial traits
54
Mitochondrial genome are usually given the prefix...?
mt
55
Why are Y-linked traits rare?
The Y chromosome is small and contains small number of genes
56
Many of the genes on the Y chromosome are....?
Sex determination
57
What is an example of an X-linked recessive trait?
Hemophilia
58
Based on X-linked traits, an allele that encodes inactive protein or no protein is generally..... (recessive or dominant)?
Recessive
59
Females affected by a mitochondrial trait, which offsprings will be affected?
All offsprings are affected, sons or daughters
60
What does population genetics consider?
Inheritance of traits in populations over time
61
What is a gene pool?
The sum total of all genetic information in a population
62
What is the Hardy-Weinberg law?
Frequencies of alleles in the gene pool of a pop'n won't change over time if they follow the assumptions
63
What are the assumptions to the Hardy-Weinberg law?
1. No mutation 2. No migration 3. No natural selection 4. Random mating 5. Pop'n large to prevent random drift
64
What is the Hardy-Weinberg equation?
p^2 + 2pq + q^2 = 1
65
When does a population reach Hardy-Weinberg equilibrium?
After one generation
66
What is fitness in relation to evolution?
How successful it is in passing on its alleles to future generations
67
Can natural selection cause new alleles to appear in the populations?
No, it cannot alter introduce genetic diversity
68
What are the two new sources of genetic variation in a population?
New alleles and new combinations of existing alleles
69
What is directional selection?
Natural selection removing the extreme and population average move in one direction over time
70
What is divergent selection?
Natural selection removes the members near the average, leaving the extremes
71
What is stabilizing selection?
Both extremes of traits are selected against, driving population closer to average
72
What is artificial selection?
Human intervene in the mating of animals and plans to achieve desired traits through controlled mating
73
What is sexual selection?
Animals have evolved rituals and physical displays that-lay key roles in attracting and choose a mate
74
What is kin selection?
Animals that live socially share alleles with other individuals and may sacrifice themselves for the sake of the alleles they share with another individual
75
What is a specie?
A group of organisms which are capable of reproducing its each other sexually
76
What is the difference between a specie and a population?
Species can mate and produce fit offspring, populations do
77
What are two types of reproductive isolations?
Pre-zygotic and post-zygotic
78
What are the five prezygotic barriers?
1. Ecological 2. Temporal 3. Behavioral 4. Mechanical 5. Gametic
79
What is the ecological prezygotic barrier?
Cannot access each other; different living areas
80
What is the temporal prezygotic barrier?
Different times of the day, season or year
81
What is the behavioural prezygotic barrier?
Special rituals or courtship behaviors before mating
82
What is the mechanical prezygotic barrier?
Reproductive structures are not compatible
83
What is the gametic prezygotic barrier?
Sperm from on species cannot fertilize egg of another
84
What are the three postzygotic barriers?
Hybrid: 1. Inviability 2. Sterility 3. Breakdown
85
What is the hybrid inviability barrier?
Offspring do not develop or mature normally
86
What is the hybrid sterility barrier?
Hybrid is born but cannot reproduce
87
What is the hybrid breakdown barrier?
Second generation hybrid is biologically defective
88
What is speciation?
Creation of new species
89
What is cladogenesis?
Branching speciation; one species diversifies and becomes two or more species
90
What is anagenesis?
One biological species becomes another by changing so much over time
91
What type of speciation is allopatric isolation?
Cladogenesis
92
What is allopatric isolation?
Geographical isolation leads to reproductive isolation
93
What is sympatric speciation?
A species gives rise to a new species in the same geographic area through divergent selection
94
What are homologous structures?
Shared features resulted from a common ancestor
95
What are analogous structures?
Structures serving the same function in two different species but not due to common ancestor
96
What is convergent evolution?
Two different species come to posses many analogous structures due to similar selective pressures
97
What is divergent evolution?
Opposite of convergent evolution; causes cladogenesis
98
What is parallel evolution?
Two species go through similar evolutionary changes due to similar selective pressures
99
What is taxonomy?
Biological classification
100
In binomial classification, each specie is given two name: ....?
A genes and a species; gene is always capitalized and species its not
101
What are the eight principal taxonomic categories?
Domain, Kingdom, Phylum, Class, Order, Family, Genus and Species
102
What is the mnemonic for the taxonomic categories?
Dum King Philip Came Over For Great Sex
103
What does anterior facing means? What about posterior?
Front-facing; back-facing
104
What is ventral based on bilateral symmetry?
Opposite of dorsal; belly button
105
In humans, based on bilateral symmetry, what is superior? What is inferior?
Towards the head, towards the feet
106
What is another way of saying towards the head other than superior? What about another way of saying inferior based on bilateral symmetry?
Cephalad; caudal
107
It is through that the early atmosphere was what? Based on that, how did it effect electron donors?
Reducing environment; electron donors were prevalent
108
What is abiotic synthesis?
Monomers spontaneously formed through rocks and clay acting as catalyst
109
Polypeptides made through abiotic synthesis are called: ______?
Proteinoids
110
What do proteinoid form in water?
Microspheres; droplets
111
What happens when lipids are added to the solution of water and protenoids?
Liposomes ad lipids forming a layer on the surface of proteins
112
What are coacervates?
Complex particles including polypeptides, nucleic acids and polysaccharides
113
What are examples of protobionts?
Microspheres, liposomes and coacervates
114
What did protobionts lacked?
Organized mechanic of heredity

MCAT BIOLOGY FLASHCARDS (23 decks)

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