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

MCAT BIO CH. 7 PART 1 Flashcards

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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
Q

What is monosomy?

A

Gamete with no copies create a zygote with one copy of a chromosome

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26
Q

What is an example of nondisjunction not being lethal in humans?

A

Trisomy of chromosome #21 results in Down syndrome

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27
Q

What is an example of nondisjunction in sex chromosomes being nonlethal?

A

Turner syndrome: organisms with 1 X and no Y

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28
Q

What are the two laws of Mendel?

A
  1. Law of segregation

2. Law of independent assortment

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29
Q

What is the law of segregation?

A

Two alleles of an individual are separated and passed on to the next generation singly

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30
Q

What is the law of independent assortment?

A

Alleles of one gene will separate into games independently of alleles for another gene

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31
Q

What is a test cross?

A

individual is crossed to another individual that has a homozygous recessive genotype

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32
Q

If the color gene and the shape gene are right next to each other on a chromosome, will they display independent assortment?

A

They would display an exception called linkage

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33
Q

What tool is used to visualize law of segregation and independent assortment?

A

Punnett square

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34
Q

What are to ways to determine the probabilities of an outcome in a cross?

A
  1. Rule of multiplication

2. Rule of addition

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35
Q

What is the rule of multiplication?

A

Probability of two independent evens occurring found by multiplying the odds of either event alone

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36
Q

What is the rule of addition?

A

Used to calculate the chances of either of two events happening

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37
Q

What is incomplete dominance?

A

Phenotype of a heterozygote is a blended mix of both alleles

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38
Q

What is codominance?

A

Two alleles are both expressed but not blended

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39
Q

Other than ABO, what other main antigen is used in blood typing?

A

Rh (rhesus) factor

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40
Q

What is the pattern of the Rh blood factor?

A

Rh^DRh^D or Rh^DRh^d (RRand Rr) are Rh positive and RhdRhd are Rh negative

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41
Q

What is pleiotropism?

A

Expression alters many different aspects of the organism’s total phenotype

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42
Q

What is polygenism?

A

Traits influenced by many difference genes are polygenic

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43
Q

What is penetrance?

A

The likelihood that a person with a given genotype will express the expected phenotype

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44
Q

What type of penetrance can alleles or mutations display?

A

High, incomplete or low penetrance

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45
Q

What is epistasis?

A

Expression alleles for one gene is dependent on a different gene

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46
Q

What are recessive lethal alleles?

A

Mutant alleles can cause death of an organism when present in a homozygous manner

47
Q

What is linkage?

A

Failure of genes to display independent assortment, located on the same chromosome

48
Q

The frequency of recombination between two genes on a chromosome is proportional to….?

A

The physical distance between the genes along the linear length of DNA molecule

49
Q

The frequency of recombinations given by….?

A

The number of recombinant phenotypes resulting from a cross divided by the total number of progeny

50
Q

What is the equation of recombination frequency? (RF)

A

RF = # of recombinants / total # of offspring

51
Q

What are the two types autosomal trait patterns?

A
  1. Autosomal dominant

2. Autosomal recessive

52
Q

What are mitochondrial traits?

A

Inherited via the mitochondrial genome through the cellular material contributed by the mother

53
Q

What does hemizygosity means and what’s an example?

A

The individual only has one copy of the chromosome in a diploid organism; mitochondrial traits

54
Q

Mitochondrial genome are usually given the prefix…?

A

mt

55
Q

Why are Y-linked traits rare?

A

The Y chromosome is small and contains small number of genes

56
Q

Many of the genes on the Y chromosome are….?

A

Sex determination

57
Q

What is an example of an X-linked recessive trait?

A

Hemophilia

58
Q

Based on X-linked traits, an allele that encodes inactive protein or no protein is generally….. (recessive or dominant)?

A

Recessive

59
Q

Females affected by a mitochondrial trait, which offsprings will be affected?

A

All offsprings are affected, sons or daughters

60
Q

What does population genetics consider?

A

Inheritance of traits in populations over time

61
Q

What is a gene pool?

A

The sum total of all genetic information in a population

62
Q

What is the Hardy-Weinberg law?

A

Frequencies of alleles in the gene pool of a pop’n won’t change over time if they follow the assumptions

63
Q

What are the assumptions to the Hardy-Weinberg law?

A
  1. No mutation
  2. No migration
  3. No natural selection
  4. Random mating
  5. Pop’n large to prevent random drift
64
Q

What is the Hardy-Weinberg equation?

A

p^2 + 2pq + q^2 = 1

65
Q

When does a population reach Hardy-Weinberg equilibrium?

A

After one generation

66
Q

What is fitness in relation to evolution?

A

How successful it is in passing on its alleles to future generations

67
Q

Can natural selection cause new alleles to appear in the populations?

A

No, it cannot alter introduce genetic diversity

68
Q

What are the two new sources of genetic variation in a population?

A

New alleles and new combinations of existing alleles

69
Q

What is directional selection?

A

Natural selection removing the extreme and population average move in one direction over time

70
Q

What is divergent selection?

A

Natural selection removes the members near the average, leaving the extremes

71
Q

What is stabilizing selection?

A

Both extremes of traits are selected against, driving population closer to average

72
Q

What is artificial selection?

A

Human intervene in the mating of animals and plans to achieve desired traits through controlled mating

73
Q

What is sexual selection?

A

Animals have evolved rituals and physical displays that-lay key roles in attracting and choose a mate

74
Q

What is kin selection?

A

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
Q

What is a specie?

A

A group of organisms which are capable of reproducing its each other sexually

76
Q

What is the difference between a specie and a population?

A

Species can mate and produce fit offspring, populations do

77
Q

What are two types of reproductive isolations?

A

Pre-zygotic and post-zygotic

78
Q

What are the five prezygotic barriers?

A
  1. Ecological
  2. Temporal
  3. Behavioral
  4. Mechanical
  5. Gametic
79
Q

What is the ecological prezygotic barrier?

A

Cannot access each other; different living areas

80
Q

What is the temporal prezygotic barrier?

A

Different times of the day, season or year

81
Q

What is the behavioural prezygotic barrier?

A

Special rituals or courtship behaviors before mating

82
Q

What is the mechanical prezygotic barrier?

A

Reproductive structures are not compatible

83
Q

What is the gametic prezygotic barrier?

A

Sperm from on species cannot fertilize egg of another

84
Q

What are the three postzygotic barriers?

A

Hybrid: 1. Inviability 2. Sterility 3. Breakdown

85
Q

What is the hybrid inviability barrier?

A

Offspring do not develop or mature normally

86
Q

What is the hybrid sterility barrier?

A

Hybrid is born but cannot reproduce

87
Q

What is the hybrid breakdown barrier?

A

Second generation hybrid is biologically defective

88
Q

What is speciation?

A

Creation of new species

89
Q

What is cladogenesis?

A

Branching speciation; one species diversifies and becomes two or more species

90
Q

What is anagenesis?

A

One biological species becomes another by changing so much over time

91
Q

What type of speciation is allopatric isolation?

A

Cladogenesis

92
Q

What is allopatric isolation?

A

Geographical isolation leads to reproductive isolation

93
Q

What is sympatric speciation?

A

A species gives rise to a new species in the same geographic area through divergent selection

94
Q

What are homologous structures?

A

Shared features resulted from a common ancestor

95
Q

What are analogous structures?

A

Structures serving the same function in two different species but not due to common ancestor

96
Q

What is convergent evolution?

A

Two different species come to posses many analogous structures due to similar selective pressures

97
Q

What is divergent evolution?

A

Opposite of convergent evolution; causes cladogenesis

98
Q

What is parallel evolution?

A

Two species go through similar evolutionary changes due to similar selective pressures

99
Q

What is taxonomy?

A

Biological classification

100
Q

In binomial classification, each specie is given two name: ….?

A

A genes and a species; gene is always capitalized and species its not

101
Q

What are the eight principal taxonomic categories?

A

Domain, Kingdom, Phylum, Class, Order, Family, Genus and Species

102
Q

What is the mnemonic for the taxonomic categories?

A

Dum King Philip Came Over For Great Sex

103
Q

What does anterior facing means? What about posterior?

A

Front-facing; back-facing

104
Q

What is ventral based on bilateral symmetry?

A

Opposite of dorsal; belly button

105
Q

In humans, based on bilateral symmetry, what is superior? What is inferior?

A

Towards the head, towards the feet

106
Q

What is another way of saying towards the head other than superior? What about another way of saying inferior based on bilateral symmetry?

A

Cephalad; caudal

107
Q

It is through that the early atmosphere was what? Based on that, how did it effect electron donors?

A

Reducing environment; electron donors were prevalent

108
Q

What is abiotic synthesis?

A

Monomers spontaneously formed through rocks and clay acting as catalyst

109
Q

Polypeptides made through abiotic synthesis are called: ______?

A

Proteinoids

110
Q

What do proteinoid form in water?

A

Microspheres; droplets

111
Q

What happens when lipids are added to the solution of water and protenoids?

A

Liposomes ad lipids forming a layer on the surface of proteins

112
Q

What are coacervates?

A

Complex particles including polypeptides, nucleic acids and polysaccharides

113
Q

What are examples of protobionts?

A

Microspheres, liposomes and coacervates

114
Q

What did protobionts lacked?

A

Organized mechanic of heredity

MCAT BIOLOGY FLASHCARDS (23 decks)

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