MT6315 L4 CHROMOSOMES

Question 1

carried traits from one generation to the next

Answer 1

Mendelian “factors”

Question 2

Who recognized and explored the fibrous network within the nucleus? And what are these networks?

Answer 2

Walther Flemming and it is chromatin or “stainable material”

Question 3

center of the cell where genetic material is formed

Answer 3

nucleus

Question 4

What did Walther Flemming observe in cell division stages?

Answer 4

observed cells in various stages of division and recognized that chromosomal movement during mitosis offered a mechanism for the precise distribution of nuclear material during cell division

Question 5

What did Theodor Boveri discover?

Answer 5

first evidence that germ cell chromosomes imparted continuity between generations

observed cells during meiosis

Question 6

What was Boveri’s profession?

Answer 6

Embryologist

Question 7

What did Boveri focus on?

Answer 7

cytoplasmic changes to see possible changes in the offspring

Question 8

What kind of embryos did Boveri work with?

Answer 8

Ascaris embryos that first depicted meiosis

Question 9

What did Walter Sutton discover?

Answer 9

described the configurations of individual chromosomes in cells at various stages of meiosis (testes of Brachystola magna) on grasshoppers

Question 10

Who confirmed and expanded upon Boveri’s observations?

Answer 10

Walter Sutton

Question 11

Sutton and Boveri’s experiments provided physical basis for?

Answer 11

physical basis of the Mendelian law of heredity – developed the “Chromosomal Theory of Inheritance

Question 12

Boveri hoped that his experiments would also help to distinguish the roles of the______ and ________ in _______.

Answer 12

nucleus and the cytoplasm; embryogenesis.

Question 13

T or F: Boveri was particularly interested in how offspring are shaped by the attributes of their parents.

Answer 13

T

Question 14

Who experimentally demonstrated Chromosomal Theory of Inheritance using Drosophila melanogaster and pioneered “Fly Room” experiments?

Answer 14

Thomas Hunt Morgan

Question 15

Who helped establish the chromosomal basis of heredity and sex?

Answer 15

Calvin Bridges

Question 16

What else did Calvin Bridges discover?

Answer 16

nondisjunction caused chromosomes, under some circumstances, to fail to separate when forming sperm and egg cells.

nondisjunction caused sperm or egg cells to contain abnormal amounts of chromosomes, and the offspring produced by the sperm or eggs would display traits that they would typically not have.

Question 17

Chromosomes are also called?

Answer 17

“colored bodies” or thread-like structures

Chroma=color
Soma=body

Question 18

Chromosomes are made of?

Answer 18

a protein and a single molecule of has DNA, and some minute RNA

Question 19

What do chromosomes do?

Answer 19

Enable transmission of genetic information from one generation to the next

Question 20

What do chromosomes do in the context of mitosis?

Answer 20

Ensure daughter cell retains complete genetic complement

Question 21

What do chromosomes do in the context of meiosis?

Answer 21

Enable each mature ovum and sperm to contain a unique single set of parental genes

Question 22

Why is having a unique set of genes important in meiosis?

Answer 22

genetic recombination protects us from diseases and create new genetically different species from parents

Question 23

How many chromosomes in the human?

Answer 23

44 autosomes
2 sex chromosomes
Extra-chromosomal DNA
̶ Other DNA materials found in the mitochondria

Question 24

How many meters of DNA in a chromosome?

Answer 24

about 2m

Question 25

How many base pairs per set of chromosomes?

Answer 25

about 3 billion

Question 26

How many genes code for proteins that perform most life structures?

Answer 26

20,000-25,000

Question 27

Replicated chromatids condensed chromosome with sister chromatid

Answer 27

Metaphase chromosome

Question 28

What is the protein that links DNA together?

Answer 28

H1 Histones

Question 29

What composes the nucleosome?

Answer 29

8 histone globus and 147 nucleotide pairs, 1 peripheral protein (H1 Histone)

Question 30

Telomeres resemble?

Answer 30

aglets of shoelace

Question 31

What is the technique that cytogeneticists employ in order to produce a banding pattern in individual chromosome?

Answer 31

G-banding

Question 32

Cytogeneticists make use of diagrams referred to as __________ to determine the ______ and ______ of chromosomes.

Answer 32

chromosome ideograms relative sizes and the banding patterns

Question 33

What are the other types of banding techniques?

Answer 33

1. Reverse (R-) banding, 2. Constitutive heterochromatin (C-) banding, 3. Quinacrine (Q-) banding, 4. Nucleolar Organizer Region (NOR-) banding, and telomeric R (T-) banding.

Question 34

Giemsa stain is a compound of? And utilizes what?

Answer 34

methylene blue-eosin and methylene blue utilizes acetic acid fixation, air drying, denaturing chromosomes mildly with proteolytic enzymes, salts, heat, detergents, or urea, and finally giemsa stain.

Question 35

Chromosome bands appear similar to those ________ by _______

Answer 35

fluorochromed by Q-banding stain

Question 36

Regions in the chromosome that stain _____with G-banding tend to be more transcriptionally active, euchromatic, and rich with guanine and cytosine.

Answer 36

rather lightly

Question 37

______ also makes use of Giemsa stain that binds to ______.

Answer 37

C-banding ; constitutive heterochromatin.

Question 38

Two identical strands which are the result of DNA replication

Answer 38

Chromatids

Question 39

What is the centromere?

Answer 39

Central region Primary constriction where sister chromatids are linked Consists of several hundred kilobases of repetitive DNA Responsible for chromosome movement at cell division

Question 40

Centromere divides the chromosome into?

Answer 40

▪ Short arm: designated as p (petite) ▪ Long arm: designated as q (queues or “g” = grande)

Question 41

What are alphoid chromosomes?

Answer 41

Centromeric regions of primate chromosomes are dominated by alphoid (alpha satellite) DNA, a family of tandemly repeated nontranscribed sequences

Question 42

Satellite DNA belongs to which region of genome?

Answer 42

the non-coding region

Question 43

Tandem repeats occur when?

Answer 43

a pattern of 2 or more nucleotides are repeated adjacent to one another.

Question 44

Satellite DNA is concentrated where?

Answer 44

near the centromere and telomere regions of chromosomes and forms a large part of heterochromatin.

Question 45

How many repeating units in alpha satellite?

Answer 45

171

Question 46

How many repeating units in beta satellite?

Answer 46

68

Question 47

How many repeating units in micro satellite?

Answer 47

2-10

Question 48

How many repeating units in mini satellite?

Answer 48

10-100

Question 49

Organelle located at the centromere region

Answer 49

Kinetochore

Question 50

Kinetochore is responsible for?

Answer 50

Microtubule Organizing Center Spindle formation

Question 51

Chromosome types based on number of centromeres?

Answer 51

Monocentric Acentric Dicentric

Question 52

genetically unstable because they cannot be maneuvered properly during cell division and are usually lost

Answer 52

Acentric

Question 53

genetically unstable because it is not transmitted in a predictable fashion

Answer 53

Dicentric

Question 54

Types of chromosomes based on centromere position?

Answer 54

Metacentric Sub-metacentric Acrocentric Telocentric

Question 55

severely off-set from centre, leading to much shorter p arm

Answer 55

Acrocentric

Question 56

centromere off-centre, leading to shorter p arm relative to q arm

Answer 56

Submetacentric

Question 57

chromosome is X shape

Answer 57

Metacentric

Question 58

centromere found at end of chromosome, meaning no p arm exists

Answer 58

Telocentric

Question 59

13 - 15, 21, 22, Y

Answer 59

Acrocentric

Question 60

2, 4 - 12, 17, 18, X

Answer 60

Submetacentric

Question 61

Not found in humans

Answer 61

Telocentric

Question 62

1st, 3rd, 16th, 19th and 20th

Answer 62

Metacentric

Question 63

5 pairs in humans

Answer 63

Metacentric, Acrocentric

Question 64

Arm ratio - 1.0-1.6/1.7

Answer 64

Metacentric

Question 65

Arm ratio - 3.0

Answer 65

Submetacentric

Question 66

Arm ratio - 3.1-6.9

Answer 66

Subtelomeric

Question 67

Arm ratio - 7.0

Answer 67

Acrocentric

Question 68

Telomere contains repeated of what sequence?

Answer 68

hexameric sequence ‘TTAGGG’

Question 69

What maintains the structure and form of the telomeres?

Answer 69

Lariat model

Question 70

region of repetitive nucleotide sequences associated with specialized proteins

Answer 70

Telomeres

Question 71

Telomere Functions in preserving chromosome stability?

Answer 71

Preventing abnormal end-to-end fusion Protecting the ends of chromosomes from degradation Ensuring complete DNA replication Having a role in chromosome pairing during meiosis

Question 72

During early meiosis, telomeres play the distinctive function of ?

Answer 72

anchoring chromosomes to the inner nuclear membrane.

Question 73

As a consequence of the nuclear membrane polarization, what happens to the telomeres?

Answer 73

telomeres cluster together into a bouquet configuration, which facilitates pairing and recombination of the homologous chromosomes

Question 74

Individuals with______ telomeres have been reported to have a longer subsequent lifespan in some studies of vertebrate species

Answer 74

longer

Question 75

What is the end of replication problem?

Answer 75

the ends of linear DNA cannot be replicated completely during lagging strand DNA synthesis, leading to progressive shortening of the telomeric DNA during each round of DNA synthesis, reducing telomeric protective capacity accepted for explaining telomere attrition during cell proliferation progressive shortening of telomeres that lowers if protective capability

Question 76

What is telomerase?

Answer 76

ribonucleoprotein enzyme which carries out the task of adding repetitive nucleotide sequences to the ends of the DNA.

Question 77

What does telomerase do?

Answer 77

Telomerase "replenishes" the telomere "cap" and requires no ATP

Question 78

Where is telomerase active in eukaryotes?

Answer 78

germ cells, some types of stem cells such as embryonic stem cells, and certain white blood cells.

Question 79

T or F: Telomerase cannot be reactivated.

Answer 79

F; it can be, reverting the telomere back into the embryonic state by somatic cell nuclear transfer

Question 80

The steady shortening of telomeres with each replication in somatic (body) cells may have a role in?

Answer 80

senescence and in the prevention of cancer

Question 81

In vitro studies have shown that telomeres accumulate damage due to _____ .

Answer 81

oxidative stress

Question 82

In Telomere damage, oxidative stress-mediated DNA damage has a major influence on_____.

Answer 82

telomere shortening in vivo.

Question 83

The phenomenon of limited cellular division was first observed by? Which is now called?

Answer 83

Leonard Hayflick, and is now referred to as the Hayflick limit.

Question 84

Additional to the Hayflick model, significant discoveries were subsequently made by?

Answer 84

a group of scientists organized at Geron Corporation by Geron's founder Michael D. West, that tied telomere shortening with the Hayflick limit.

Question 85

Theodor Boveri developed the chromosomal theory of inheritance and the idea of?

Answer 85

Chromosomal individuality

Question 86

Who are the pioneers for the discovery of sex chromosomes and association between specific genes and specific chromosomes?

Answer 86

Thomas Hunt Morgan Calvin Bridges

Question 87

T or F: Calvin Bridges also used Drosophila to prove his experiments in nondisjunction

Answer 87

T

Question 88

What is an example of a mitochondrial sickness?

Answer 88

MELAS (Mitochondrial Encephalopathy, Lactic Acidosis, and Stroke-like episodes)

Question 89

What protects the end of the chromosomes?

Answer 89

Telomeres

Question 90

What wraps around the histone octamer?

Answer 90

DNA double helix

Question 91

When nucleosomes bind together, what forms?

Answer 91

A 3-D zigzag structure with histone H1 and other DNA-binding proteins

Question 92

Condensed nucleosomes form what structure? What binds these together?

Answer 92

Solenoid structure, bound together by bent Linker DNA

Question 93

Cytogeneticists employ staining techniques to determine the pattern of?

Answer 93

Characteristic pattern of light and dark bands

Question 94

Chromosomal shorthand for DiGeorge Syndrome?

Answer 94

del22q 11.2

Question 95

Chromosomal shorthand for Cystic fibrosis transmembrane conductance regulator (CF)?

Answer 95

7q 31.2

Question 96

5-300 base pairs long and are part of the high evolving eukaryotic genome

Answer 96

Satellite DNA

Question 97

Location of beta-satellites?

Answer 97

In the pericentric region

Question 98

What kind of satellite DNA is dispersed all throughout the chromosome?

Answer 98

Microsatellite

Question 99

What Satellite DNA is found in the telomeric region?

Answer 99

Minisatellite

Question 100

The kinetochore contains how many regions? What are these regions and their functions?

Answer 100

Inner kinetochore - tightly associated with the centromere Outer kinetochore - interacts with microtubules

Question 101

Chromosome type that is a broken fragment left after breaking off from a chromosomal fragile site

Answer 101

Acentric

Question 102

Chromosomal type that is left in the metaphase plate because of the lack of kinetochores

Answer 102

Acentric

Question 103

Chromosome type that fused chromosomes in cases precipitated by conditions like Robertsonian translocation

Answer 103

Dicentric

Question 104

What are the metacentric chromosomes?

Answer 104

1,3,16,19,20

Question 105

What are the submetacentric chromosomes?

Answer 105

2,4-12,17,18,X

Question 106

What are the Acrocentric chromosomes?

Answer 106

13-15,21,22,Y

Question 107

In Acrocentric chromosomes, the p arm is very short, thus they are considered as?

Answer 107

satellite regions

Question 108

T or F: Loss of the satellite regions in the acrocentric chromosomes will still lead to genetic aberrations

Answer 108

T

Question 109

During anaphase, what is the shape of metacentric chromosomes?

Answer 109

V shaped

Question 110

During anaphase, what is the shape of submetacentric chromosomes?

Answer 110

J shaped

Question 111

During anaphase, what is the shape of acrocentric chromosomes?

Answer 111

I shaped

Question 112

Where are telocentric chromosomes usually found?

Answer 112

In Oxalis (Shamrock)

Question 113

Who created the chromosome type based on arms ratio?

Answer 113

Levan et al

Question 114

What is another name for arm ratio in chromosomes? Hint: It's an equation

Answer 114

L/S

Question 115

What protein is responsible for the packaging of DNA in the cell nucleus? Why is this necessary?

Answer 115

Histones (H1 histones, histone octamers) This is important to make DNA be able to fit into the nucleus, needs to be tightly packed

Question 116

What is the role of telomeres in cancer development?

Answer 116

As a cell begins to become cancerous, it divides more often, and its telomeres become very short. If its telomeres get too short, the cell may die. Often times, these cells escape death by making more telomerase enzyme, which prevents the telomeres from getting even shorter.