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Test 1 Flashcards

1
Q

What is sexual reproduction?

A

The formation of offspring that are genetically distinct from their parents

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2
Q

Among most eukaryotes, sexual reproduction consists of what two processes?

A

Meiosis produces haploid gametes and fertilization produces diploid zygotes from the gametes

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3
Q

Sex refers to what?

A

Sexual phenotype

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4
Q

What is the fundamental difference between males and females?

A

males produce small gametes and females produce relatively large gametes

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5
Q

What is sex determination?

A

The mechanism by which biological sex is established

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6
Q

How to define the sex of an individual organism reference?

A

phenotype

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7
Q

What is gender?

A

It is a category assigned by the individual or others based on behavior and cultural practices

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8
Q

What is hermaphroditism?

A

Both sexes are present in the same organism

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9
Q

What is monoecious?

A

Species in which an individual organism has either male or female reproductive structures

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10
Q

Among dioecious species, how sex can be determined?

A

Chromosomally, genetically, or environmentally

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11
Q

What is the Chromosome theory of heredity?

A

It states that genes are located on chromosomes which serve as vehicles for the segregation of genes in meiosis

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12
Q

What are sex chromosomes?

A

Chromosomes differ between males and females

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13
Q

What is autosomes?

A

Nonsex chromosomes, which are the same for males and females

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14
Q

What is responsible for the sexual phenotypes?

A

Genes located on sex chromosomes in conjunction with genes located on autosomes

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15
Q

What occurs in the XX-XO systems?

A

Females have XX and Males have XO

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16
Q

What does O chromosomes mean?

A

The letter O signifies the absence of a sex chromosome

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17
Q

What occurs in meiosis with the XX-XO system?

A

From the females, one X chromosome enters the haploid egg. From the males, a single X chromosome segregates in meiosis and the other half receives no chromosomes.

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18
Q

What is heterogametic sex?

A

It is a sex produces two different types of gametes with respect to the sex chromosomes

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19
Q

What is homogametic sex?

A

It is a sex that produces the same gametes

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20
Q

In the XX-XO system, how is the sex of an individual determined?

A

It determines which type of male gamete fertilizes the egg.

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21
Q

In humans, the Y chromosomes are considered what?

A

acrocentric (not-Y-shaped)

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22
Q

The X and Y chromosomes are homology only where?

A

pseudoautosomal regions

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23
Q

Why is the pseudoautosomal region essential?

A

For X-Y chromosome pairing in meiosis in the male

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24
Q

True or False: X and Y chromosomes are generally homologous

A

They are not generally homology but they do pair and segregate in different cells in meiosis

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25
What occurs in ZZ-ZW sex-determining system?
Females have ZW and males have ZZ
26
What is genic sex determination?
Genotypes of one or more loci determine the sex of an individual
27
What is sex determined by?
individual genes
28
In both genic sex determination and chromosomal sex determination, sex is controlled by what?
individual genes
29
What is sequential hermaphroditism?
Each individual animal can be both male and female but not at the same time
30
What are examples of XX-XO systems?
Grasshoppers and some insects
31
What are examples of XX-XY systems?
Insects, fishes, amphibians, reptiles, mammals
32
What are examples of ZZ-ZW systems?
Butterflies, birds, some reptiles and amphibians
33
What are examples of genic sex determination?
plants, fungi, protozoans, and fishes
34
What are examples of environmental sex determination?
invertebrates, turtles, and alligators
35
How else sexual phenotype can be determined by? Hint: Fruit Flyes
X chromosomes to Autosomes chromosomes
36
X:A is 1.0 sexual phenotype?
Female
37
X:A is 0.5 sexual phenotype?
Male
38
X:A is less than 0.5 sexual phenotypes?
Metamale
39
X:A is more than 1.0 sexual phenotypes?
Metafemale
40
The male is primarily determined by the presence of what?
SRY genes
41
What is Turner syndrome?
Females that have underdeveloped second-sex characteristics. They have some XO chromosomes
42
What is Klinefelter syndrome?
People have cells with one or more Y chromosomes and multiple X chromosomes
43
What is triple X syndrome?
Females process XXX chromosomes
44
What sex chromosomes contain genetic information essential for both sexes?
X chromosomes
45
What is a male-determining gene usually locating on which chromosomes?
Y chromosomes
46
Additional copies of the X chromosomes may lead to what in both males and females?
Disabilities
47
What is nondisjunction?
when chromosomes fail to separate in anaphase I in meiosis
48
Z linked is same as X linked by what is the difference?
sex role are reverse
49
What chromosomes do females have?
two copies of X Chromosome and two copies of each autosomes
50
What is dosage compensation?
It is achieved by a doubling of the activity of the genes on the X chromosomes of males
51
Bridge's Hypothesis
Involves Nondisjunction?
52
What is Barr Bodies?
Darkly staining bodies in the nuclei of cells
53
What is Lyon Hypothesis?
Barr Body was an inactive X chromosome
54
From XXXXX (Poly-X female), how many barr bodies
4
55
What does Lyon hypothesis suggest?
The presence of variable number of X chromosomes should not affect the phenotype in mammals because any X chromosomes in excess of one should be inactivated
56
What is a gene?
An inherit factor that helps determine a characteristic
57
What is an allele?
One of two or more alternative forms of a gene
58
What is a locus?
A specific place on a chromosome occupied by an allele
59
What is a genotype?
A set of alleles possessed by an individual organism
60
What is homozygote?
An individual organism possessing two of the same alleles at a locus
61
What is heterozygote?
An individual organism possessing two different alleles at a locus
62
What is a characteristic or a character?
An attribute or feature possessed by an organism
63
What is a phenotype or trait?
The appearance or manifestation of a character
64
What is monohybrid crosses?
Crosses between parents that different in a single characteristic
65
What is parental generation?
first generation of a cross
66
What are F1?
Offsprings of the first generation
67
What are the observations of the principle of segregation?
Each individual organism possesses two alleles encoding a trait. Alleles separate when gametes are formed. Alleles are separate in equal proportions.
68
What stage of meiosis that each individual organism possesses two alleles encoding a trait?
Before meiosis
69
What stage of meiosis that alleles separate when gametes are formed?
Anaphase I
70
What stage of meiosis that alleles are separate in equal proportions?
Anaphase I
71
What are observations of principles of Independent Assortment?
Alleles at different loci separate independently
72
What stage of meiosis that alleles at different loci separate independently?
Anaphase I
73
What is backcross?
cross between F1 genotype and parental genotype
74
What ratio of dihybrid crosses?
9:3:3:1
75
What is a prokaryote?
A unicellular organism that lacks a nucleus and only has a plasma membrane
76
What is a eukaryote?
A multicellular or unicellular organism where the nucleus is present and bounded by a membrane
77
What type are prokaryotes?
Bacteria and Archaea
78
What is the major difference between prokaryote and eukaryotic cells?
In eukaryotic has a nuclear membrane which surrounds the genetic material to form a nucleus
79
How chromosomes are formed?
DNA formed with histones (proteins)
80
What is chromatin?
Complex of DNA and histone proteins
81
How do histone proteins regulate?
Histone proteins help regulate the accessibility of DNA to enzymes and other proteins that copy and read the DNA and enable the DNA to fit into the nucleus
82
What does Bacteria don't process with their DNA?
Bacteria do not possess histones
83
What are viruses?
It is neither prokaryotic nor eukaryotic because they do not possess the structure of a cell
84
What are the three fundamental events that must take place for cell division?
1) its genetic information must be copied 2) the copies must be separated from each other 3) the cell must divide
85
How does a prokaryotic cell reproduce?
Binary Fission
86
What is the binary fission?
When a single circular chromosome replicates
87
What is the origin of replication?
Replication occurs at this place
88
What are diploid cells?
Cells that carry two sets of genetic information
89
What is a functional chromosome?
a centromere, pair of telomeres, and origin of replication
90
What is the purpose of the centromere?
It serves as the attachment point for spindle microtubules
91
What are telomeres?
It protects and stabilizes the chromosome ends
92
What are checkpoints in cell cycle?
Progression through the cell cycle is regulated at key transition points which allow or prohibit the cell's progress to the next stage
93
What is the interphase?
The period between cell divisions in which the cell grows develops, and function
94
What is the mitotic phase?
the period of active cell division
95
What does M phase include?
mitosis, the process of nuclear division and cytokinesis
96
What are condensins?
A group of proteins that bind to the DNA within chromosomes and bring about condensation that occurs in prophase
97
What do microtubules consist of?
Tublin
98
What is G0 phase?
Stable nondividing period of variable length
99
What is G1 phase?
Growth and development of the cell
100
What is S phase?
Synthesis of DNA
101
What is G2 phase?
Preparation for division
102
Which cell division where chromosomes are reduced in half?
Meiosis
103
What stage of meiosis is termed as reduction division?
Meiosis I
104
What stage of meiosis is termed as equational division?
Meiosis II
105
What is synapsis?
homologous chromosomes pair up and begin synapsis a very close pairing association
106
What is bivalent or tetrad?
Each homologous pair of synapsed chromosomes
107
When does synapsis occur?
Prophase I
108
What is crossing over?
Homologous chromosomes exchange genetic information take place in prophase I
109
What is interkinesis?
The period between meiosis I and II. The nuclear membrane reforms
110
What is recombination?
The creation of new combinations of alleles on a chromatid
111
What must be taken for recombination?
Crossing Over
112
When does random alignment take place?
Metaphase I
113
What is cohesion?
A protein that holds chromatids together
114
Where does cohesin along chromosome arms hold homologs together at?
Chiamata
115
Coshesin at the centromere is protected by a protein called
Shugoshin
116
When is the centromeric cohesin no longer protected by shugoshin?
Metaphase II
117
When does synapsis form?
Zygotene
118
When does the synaptonemal complex develop?
Pachytene

Biology 142 (1 decks)

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