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Fundamentals of Genetics (lec) > Chromosomal Basis of Heredity > Flashcards

Chromosomal Basis of Heredity Flashcards

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Biology 101 flashcards
1
Q

The first cells

A

Prokaryotes

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2
Q

Cells that lack a nucleus or membrane-bound organelles: nucleus, ER, mitochondria, golgi apparatus, chloroplast

includes bacteria

A

Prokaryotes

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3
Q

What is the shape of a prokaryote chromosome

A

Circular

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4
Q

Where is the DNA found in prokaryotes

A

Nucleoid region

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5
Q

What organelle make proteins

A

Ribosomes

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6
Q

Eukaryotes contain 3 basic cell structures:

A
  1. Nucleus
  2. Cell membrane
  3. Cytoplasm with organelles
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7
Q

Fluid, jelly-like substance between the cell membrane and the nucleus in which organelles are suspended

Serves as matrix substance in which chemical reactions occur

A

Cytoplasm

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8
Q

Granular particles composed of protein and RNA

Synthesize proteins

A

Ribosomes

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9
Q

Cluster of flattened membranous sacs that synthesize carbohydrates and packages molecules for secretion, secretes lipids and glycoproteins

A

Golgi complex

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10
Q

Membranous sacs with folded inner partitions that release energy from food molecules and transform energy into usable ATP

A

Mitochondria

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11
Q

Membranous sacs that digest foreign molecules and worn and damaged organelles

A

Lysosomes

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12
Q

Metabolizes nonpolar compounds and stores Ca2+ in striated muscle cells

A

Agranular (smooth) endoplasmic reticulum

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13
Q

Which ER assists in protein synthesis

A

Granular (rough) endoplasmic reticulum

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14
Q

Spherical membranous vesicles that contain enzymes that detoxify harmful molecules and break down hydrogen peroxide

A

Peroxisomes

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15
Q

Nonmembranous mass of two rod-like centrioles that helps organize spindle fibers and distribute chromosomes during mitosis

A

Centrosome

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16
Q

Membranous sacs that store and release various substances within the cytoplasm

A

Vacuoles

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17
Q

Thin, hollow tubes that support cytoplasm and transport materials within the cytoplasm

A

Microfilaments and microtubules

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18
Q

Minute cytoplasmic projections that extend from the cell surface that move particles along cell surface or move the cell

A

Cilia and flagella

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19
Q

Double-layered membrane that surrounds the nucleus, composed of protein and lipid molecules

Supports nucleus and controls passage of materials between nucleus and cytoplasm

A

Nuclear envelope

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20
Q

Fibrous strands composed of protein and DNA that contains genetic code that determines which proteins (including enzymes) will be manufactures by the cell

A

Chromatin

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21
Q

theory that states that some organelles within cells were at one time free living cells themselves

Supporting evidence included organelles
with their own DNA:
Chloroplast and Mitochondria

A

Endosymbiotic theory

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22
Q

Mitochondria Come from cytoplasm in the EGG cell during fertilization

Therefore …

You inherit your mitochondria from your mother

A
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23
Q

Most eukaryotes have between __ and
___ chromosomes in their body cells

A

10 and 50

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24
Q

Human body cells have __ chromosomes or __ identical pairs

A

46
23

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25
Q

Each chromosome is composed of a single, tightly coiled DNA molecule

Chromosomes can’t be seen when cells aren’t dividing and are called chromatin

A
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26
Q

Duplicated chromosomes are called ___________ & are held together by the ___________

A

chromatids
centromere

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27
Q

The shorter arm of the chromatid is the

A

p arm

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28
Q

The longer arm of the chromatid is called the

A

q arm

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29
Q

shape of the chromosome during anaphase is determined by the position of the centromere during metaphase

A
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30
Q

centromere is located in the middle

A

Metacentric

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31
Q

centromere is located between the middle and the end (3/4)

A

Submetacentric

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32
Q

centromere is located close to the end

A

Acrocentric

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33
Q

centromere is located at the end

A

Telocentric

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34
Q

When are sister chromatids formed

A

Formed during the DNA replication in the S phase of the Interphase

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35
Q

Homologous chromosomes do not stick together whereas sister chromatids are joined by their centromere

A
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36
Q

How many DNA strands do Homologous chromosomes have

A

4

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37
Q

How many DNA strand do sister chromatids have

A

1

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38
Q

Chromosomes that have identical gene sites along their lengths : locus

identical in the traits that they influence and in their genetic potential

A

Homologous Chromosomes

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39
Q

diploid organism - biparental inheritance
* two copies of each gene as a consequence of inheritance from two parents

A
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40
Q

Homologous chromosomes exceptions

A
  1. Sex-determining chromosomes
    -often not homologous in size, centromere placement, arm ratio, or genetic content
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41
Q

which sex chromosome is smaller and lacks most of the gene loci contained on the X

A

Y chromosome

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42
Q

X and Y chromosomes are not strictly homologous

  • contain homologous regions and behave as homologs in meiosis so that gametes produced by males receive either one X or one Y chromosome

Pseudoautosomal regions

A
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43
Q

Types of cell reproduction

A

Asexual reproduction
ex. Mitosis and Binary Fission

Sexual reproduction
ex. Meiosis

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44
Q
  • Prokaryotes such as bacteria divide into 2 identical cells by the process of binary fission
  • Single chromosome makes a copy of itself

-Cell wall forms between the chromosomes dividing the cell

A
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45
Q

Five phases of cell cycle

A
  1. G1 - primary growth phase
  2. S - synthesis; DNA replicated
  3. G2 - secondary growth phase
    * collectively these 3 stages are called interphase
  4. M - mitosis
  5. C - cytokinesis
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46
Q

Time spent by cell to undergo Interphase and Mitosis

A

Interphase
G1 = 5 hrs
S = 7 hrs
G2 = 3 hrs
Mitosis = 1 hr

P = 36 mins.
M = 3 mins.
A = 3 mins.
T = 18 mins.

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47
Q

Phase wherein:
1st growth stage after cell division

Cells mature by making more cytoplasm & organelles

Cell carries on its normal metabolic activities

A

Interphase - G1 stage

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48
Q

Stage wherein:
Cells remain viable and metabolically active

Not proliferative

Cancer cells avoid entering or pass it very quickly

Other cells enter and never reenter the cell cycle

Other cells can be stimulated to return to G1 and reenter the cell cycle

A

G0 stage

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49
Q

✓Synthesis stage
✓DNA is copied or replicated

A

Interphase - S stage

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50
Q

2nd Growth Stage

Occurs after DNA has been copied

All cell structures needed for division are made (e.g. centrioles)

Both organelles & proteins are synthesized

A

Interphase - G2 stage

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51
Q

✓In plant cells, ______ forms at the equator to divide cell
✓In animal cells, _____ forms to split cell

A

cell plate
cleavage furrow

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52
Q

Division of nucleus is also called

A

Karyokinesis

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53
Q

How many stages does mitosis have

A

4

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54
Q

Chromosomes are extended and uncoiled, forming chromatin

A

Interphase

55
Q

Chromosomes coil up and condense, centrioles divide and move apart

A

Prophase

56
Q

Chromosomes are clearly double structures; centrioles reach the opposite poles; spindle fibers form

A

Prometaphase

57
Q

Centromeres align on metaphase plate

A

Metaphase

58
Q

Centromeres split and daughter chromosomes migrate to opposite poles

A

Anaphase

59
Q

Daughter chromosomes arrive at the poles; cytokinesis commenses

A

Telophase

60
Q

What happens in prophase

-Nuclear membrane disintegrates and nucleolus disappears
-Chromosomes condense
-Mitotic spindle begins to form and is complete at the end of prophase
-Kinetochores begin to mature and attach to spindle

A
61
Q

What happens in Metaphase

-Kinetochores attach chromosomes to mitotic spindle and align them along metaphase plate at equator of the cell

A
62
Q

Sister chromatids are pulled apart to opposite poles of the cell by kinetochore fibers

A

Anaphase

63
Q

multi-subunit protein complex that holds together sister chromatids

A

Cohesin

64
Q

Once properly attached to the spindle fibers, cohesion is degraded by this enzyme

A

Separase

65
Q

protects cohesion from being degraded by separase at the centromeric regions

A

Shugoshin

66
Q

Anaphase disjunction:

For complete disjunction to occur:

A

(1) shugoshin must be degraded, reversing its protective role
(2) the cohesin complex holding the centromere region of each sister chromosome is then cleaved by separase
(3) sister chromatids of each chromosome are pulled toward the opposite poles of the cell

67
Q

What happens in Anaphase

-Kinetochore microtubules shorten, separating chromosomes to opposite poles
-Polar microtubules elongate, preparing cell for cytokinesis

A
68
Q

What happens in Telophase

-Chromosomes reach poles of each cell
-Kinetochores disappear
-Polar microtubules continue to elongate, preparing cell for cytokinesis
-Nuclear membrane reforms
-Nucleolus reappears
-Chromosomes decondense

A
69
Q

✓Means division of the cytoplasm
✓Division of cell into two, identical halves called daughter cells

A

Cytokinesis

70
Q

cell division cycle (cdc) mutations was first discovered in which organism

A

Yeasts

71
Q

= normal products of many of the mutated genes are enzymes that can add phosphates to other proteins.
* serve as “master control” molecules functioning in conjunction with proteins called cyclins

A

Kinases

72
Q
  • bind to these kinases (creating cyclin-dependent kinases), activating them at appropriate times during the cell cycle.
  • activated kinases then phosphorylate other target proteins that regulate the progress of the cell cycle
A

Cyclins

73
Q

G1/S checkpoint

  • monitors the size the cell has achieved since its previous mitosis and also evaluates the condition of the DNA.
  • If cell has not reached an adequate size or if the DNA has been damaged, further progress through the cycle is arrested until these conditions are “corrected”
  • If both conditions are “normal” at G1/S, then the cell is allowed to proceed from G1 to the S phase of the cycle
A
74
Q

G2/M checkpoint

  • where DNA is monitored prior to the start of mitosis
  • If DNA replication is incomplete or any DNA damage is detected and has not been repaired, the cell cycle is arrested
A
75
Q

M checkpoint

  • final checkpoint sometimes referred to as the _________
  • the successful formation of the spindle fiber system and the attachment of spindle fibers to the kinetochores associated with the centromeres are monitored
  • If spindle fibers are not properly formed or if attachment is inadequate, mitosis is arrested
A

Spindle Assembly Checkpoint

76
Q

are special proteins that increase the chance that a normal cell develops into a tumor cell

A

Oncogenes

77
Q

✓Original cell is diploid (2n)
✓Four daughter cells produced that are monoploid
(1n)
✓Occurs in the testes in males (Spermatogenesis)
✓Occurs in the ovaries in females (Oogenesis)
✓Occurs in our germ cells that produce gametes

A

Meiosis

78
Q

2 meiotic divisions

A

Reductional division
Equational division

79
Q

is the process of duplicating a chromosome

A

Replication

80
Q

Replicated copies are called

A

sister chromatids (same genes, same allele)

81
Q

Same genes, different alleles are calles

A

Homologs

82
Q

Substages of Meiotic Prophase I

A
  1. Leptonema
    = Interphase chromatin material begins to condense
    = Chromosomes still extended, become visible w/ chromomeres, localized condensations that resemble beads on a string
    = homology search: precedes and is essential to the initial pairing of homologs, begins
  2. Zygonema
    = chromosomes continue to shorten and thicken
    = rough pairing of homologous chromosomes
    = synaptonemal complex begins to form between the homologs
  3. Pachynema
    = synapsis, a more intimate pairing
    = each homolog now evident as a double structure
    = each bivalent contains four member chromatids
    = tetrad, contains two pairs of sister chromatids
  4. Diplonema
    = within each tetrad, each pair of sister chromatids begins to separate.
  5. Diakinesis
    = chromosomes pull farther apart
    = nonsister chromatids remain loosely associated at the chiasmata
    = separation proceeds, chiasmata move toward the ends of the tetrad
    = nucleolus and nuclear envelope break down
83
Q

a point where nonsister chromatids have undergone genetic exchange through crossing over

A

Chiasma

84
Q

Homologous pairs of chromosomes align along the equator of the cell

A

Metaphase I

85
Q

Homologs separate and move to opposite poles

Sister chromatids remain attached at their centromeres.

A

Anaphase I

86
Q

Nuclear envelopes reassemble.

Spindle disappears

Cytokinesis divides cell into two.

A

Telophase I

87
Q

Only one homolog of each chromosome is present in the cell.

A

Meiosis II

88
Q

Meiosis II produces gametes with one copy of
each chromosome and thus one copy of each
gene.

A
89
Q

Nuclear envelope fragments.

Spindle forms.

A

Prophase II

90
Q

Chromosomes align along equator of cell

A

Metaphase II

91
Q

Sister chromatids separate and move to opposite poles

A

Anaphase II

92
Q

Nuclear envelope assembles

Chromosomes decondense.

Spindle disappears.

Cytokinesis divides cell into two.

A

Telophase II

93
Q

Reductional division results in dyads

Equational division results in monads

A
94
Q

order of substages in Meiotic prophase I

A

Leptonema
Zygonema
Pachynema
Diplonema
Diakinesis

95
Q

are the germ cells that will eventually
develop into the mature sperm or egg

A

Spermatogonia and oogonia

96
Q

Primary spermatocyte or oocyte:
*the first step in this development is the
duplication of homologous chromosomes
to get ready for meiosis

Secondary spermatocyte or oocyte:
* the first meiotic division separates the homologous chromosomes from each parent

Spermatids or eggs:
* the second meiotic division separates the 2 chromatids and creates 4 haploid cells

A
97
Q

In males, this eventually produces _ sperm cells by the process of spermiogenesis

A

4

98
Q

In females, it produces _ egg and _ polar
bodies. This allows the egg to retain
more cytoplasm to support early stages
of development

A

1
3

99
Q

Meiosis generates tremendous genetic diversity. How many different types of gametes can be generated by an individual (male or female) with 23 different chromosomes?

A

More than 2^23 or 8,000,000 different gametes

100
Q

In males, the spermatogonia enter meiosis and produce sperm from puberty until death.

The process of sperm production takes only a few weeks.

A
101
Q

Each ejaculation has 100 to 500 million sperm.

A
102
Q

In females, the first meiotic division starts before birth but fails to proceed.

It is eventually completed about one month before ovulation in humans.

In humans, the second meiotic division occurs just before the actual process of fertilization occurs.

A
103
Q

all meiosis is ended in females at menopause.

A
104
Q

Each pair of chromatids is connected by __________.

A

axial proteins

105
Q

The 2 homologous chromosomes are held
together closely by ________.

A

central element proteins (synaptonemal complex)

106
Q

Trisomy 21

Failure of 2 chromatids to separate during meiosis II -> results in one oocyte receiving 2 instead of 1 chromatid

It results in short stature, round face and mild to severe mental retardation

A

Down syndrome

107
Q

Immature egg called

A

oocyte

108
Q

matured oocyte is called

A

ovum (egg)

109
Q

OOCYTES HAVE A VERY SMALL NUCLEUS / CYTOPLASM RATIO

A
110
Q

Ribosomal RNA genes are often amplified in oocytes. This allows more templates to
transcribe more rRNA.

A
111
Q

Dense nonmembranous mass composed of protein and RNA molecules

Produces rRNA for ribosomes

A

Nucleolus

112
Q

Surrounded by cell membrane & cell wall

A

peptidoglycan

113
Q

Many mutations that exert an effect at one or another stage of the cell cycle

A

Cell Division Cycle (cdc) Mutations

114
Q

A __________ forms that contains enzymes for cutting and splicing DNA.

A

recombination nodule

115
Q

Chromosomes are cut and joined crosswise at points called _______, seen when they separate.

A

chiasmata

116
Q

Chromosomal aberrations can be caused by..

A

nondisjunction
translocation

116
Q
  • Chromosomes fail to separate during oogenesis or spermatogenesis
  • Inherit too many or too few X or Y chromosomes
A

Nondisjunction

117
Q

-> 45,X or 45,X0
-> loss of 2nd sex chromosome
-> affects females
-> short stature, reduced functioning of ovaries

A

Turner syndrome

118
Q

-> 47,XXY
-> male has an extra X chromosome
-> affects testicular growth, resulting in smaller than normal testicles = lower production of testosterone
-> reduced muscle mass, body and facial hair, enlarged breast tissue

A

Klinefelter syndrome

119
Q

Trisomy 13
-> severe intellectual disability and physical abnormalities in many parts of the body
-> heart defects, brain/spina cord abnormalities, microphthalmia, extra fingers/toes, cleft lip with or without palate, and hypotonia
-> deafness and cardiac anomalies

A

Patau syndrome

120
Q

cause of chromosomal aberration:
- bits of chromosomes that are re-attached to other chromosomes

A

translocation

121
Q
  • Extra complete sets of chromosomes
  • 3N, 4N, 5N, etc.
A

Polyploidy

122
Q
  • Extra or missing single chromosomes
  • 2N + 1, 2N -1, etc
A

aneuploidy

123
Q

Changes in the location of genes

A
  • inversions: 180o rotation
  • translocations: exchange
  • transpositions: gene “hopping”
  • Robertsonian changes: fissions or fusions
124
Q

prenatal test that involves extracting a small amount of amniotic fluid from the uterus to assess the health of the fetus

performed during 2nd trimester = week 14-17

A

Amniocentesis

125
Q

*Genotype is XXX (47 chromosomes, extra X, trisomy)

A

Super Female or Triple X Syndrome

126
Q

▪Genotype is XYY (47 chromosomes, extra Y, trisomy)
▪Males only (1 in a 1000)
▪Usually tall (above 6 feet), slender and generally appear and act normal.
▪Produce high levels of testosterone. During adolescence they usually have severe facial acne and are poorly coordinated. They are usually fertile.
▪May be: antisocial and/or aggressive and may have below average intelligence/learning difficulties.

A

Super Male or XYY Syndrome

127
Q

Trisomy 18

Multiple congenital malformation of many organs, malformed ears, small mouth and nose with general elfin appearance.

90% die in the first 6 months.

A

Edward’s syndrome

128
Q

provides biochemical identity at the
surface of cells

A

glycocalyx or cell coat

129
Q

The portions of DNA that encode rRNA are collectively referred to as the

A

nucleolus organizer region, or the NOR

130
Q

In the cytoplasm, a nonparticulate, colloidal material referred to as the ______ surrounds and encompasses the cellular organelles

A

cytosol

131
Q

what proteins are microfilaments derived from

A

actin

132
Q

Collectively, the genetic information contained in a haploid set of chromosomes constitutes the ________ of the species

A

genome

133
Q

the shortest stage of mitosis

A

anaphase

Fundamentals of Genetics (lec) (13 decks)

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