2.1 - Chromosome Discovery and Chromosome Structure

Question 1

Who is the father of Genetics?

Answer 1

Gregor Mendel

Question 2

These are carried traits from one generation to the next

Answer 2

Medelian “factors”

Question 3

He recognized and explored the fibrous network within the nucleus which is termed now as chromatin or “stainable material”

Answer 3

Walther Flemming

Question 4

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

Answer 4

Walther Flemming

Question 5

He provided the first evidence that germ cell chromosomes imparted continuity between generations

Studied cytoplasmic changes to form new offspring from union of gametes

Answer 5

Theodor Boveri

Question 6

His work on Ascaris embryos provided one of the first descriptions of meiosis

Answer 6

Theodor Boveri

Question 7

He is one of the pioneers of embryology

Answer 7

Theodor Boveri

Question 8

He confirmed and expanded upon Boveri’s observations

Answer 8

Walter Sutton

Question 9

He described the configurations of individual chromosomes in cells at various stages of meiosis (testes of Brachystola magna or grasshopper)

Answer 9

Walter Sutton

Question 10

Flemming - studied mitosis; Sutton & Boveri studied ________

Answer 10

meiosis

Question 11

The division in meiosis can be described at both the ____ level and ____ level

Answer 11

nuclear level ; chromosomal level

Question 12

Out of the 4 products of meiosis in females, only ____ of them becomes a mature egg (ovum), while the ____ becomes polar bodies

Answer 12

1 ovum ; 3 polar bodies

Question 13

He investigated the mechanisms of heredity and developed the Chromosomal theory of inheritance and the Idea of chromosomal individuality

Answer 13

Theodor Boveri

Question 14

Boveri hoped that his experiments would also help to distinguish the roles of the nucleus and the cytoplasm in ___________

Answer 14

embryogenesis

Question 15

It is the influence that certain cytoplasmic contents have on the behavior of the nucleic material and the differentiation of the cell.

Answer 15

Cytoplasmic specification

Question 16

True or False

Boveri was also able to demonstrate that each chromosome carried specific hereditary information, and that the chromosomes were not interchangeable—they summed to the total hereditary structure

Answer 16

True

Question 17

In 1910, ge experimentally demonstrated Chromosomal Theory of Inheritance using Drosophila melanogaster

Answer 17

Thomas Hunt Morgan

Question 18

What insect did Morgan used for his “Fly Room” experiments?

Answer 18

Drosophila melanogaster or Fruit fly

Question 19

In 1916, he helped establish the chromosomal basis of heredity and sex through nondusjunction

student of Morgan

Answer 19

Calvin Bridges

Question 20

It is the procsses that causes chromosomes, under some circumstances, to fail to separate when forming sperm and egg cells

Answer 20

Nondisjunction

It caused sperm or egg cells to contain abnormal amounts of chromosomes

Question 21

These are threadlike structures or “colored bodies” (chroma = color ; soma = body)

Factors that distinguish one species from another

Answer 21

chromosome

Question 22

What are the components of a chromosome?

Answer 22

• protein
• single molecule of DNA (runs several thousands of kilobases)
• some minute RNA

Question 23

In what experiemt did scientists prove that it is in fact DNA and not protein that is being passed from gen to another?

Answer 23

rough and smooth strain bacteria

Question 24

The number of stained regions

Question 25

What factors of a chromsome distinguishes one specie to another?

Answer 25

- number - sets of genes

Question 26

It is a type of protein found in chromosomes and binds to DNA and give chromosomes their shape, and help control the activity of genes

Answer 26

Histone proteins

Question 27

What type of protein wraps and pulls around the chromosome? - it is involved in the wrapping of DNAs until it becomes a hyperlooped structure and creates the chromosome

Answer 27

Histone proteins

Question 28

# True or False All chromosomes have a constriction/region of centromere

Answer 28

False

Question 29

In ________, chromosomes ensure daughter cell retains its own complete genetic complement

Answer 29

Mitosis

Question 30

In ________, chromosomes enable each mature ovum and sperm to contain a **unique single set** of parental genes | stage where diploid (2n) becomes haploid

Answer 30

Meiosis I

Question 31

What comprises of the human chromosome?

Answer 31

* 44 autosomes * 2 sex chromosomes

Question 32

Among the phases under mitosis, which phase contains the chromosomes that are thick, easily stained, and used in karyotyping?

Answer 32

Metaphase chromosomes | Replicated condensed chromosome with sister chromatids

Question 33

In aligning the chromosomes in karyotyping, what should be the order of the chromosomes?

Answer 33

Biggest to smallest (according to size)

Question 34

In the sex chromosomes (X & Y), which is smaller in size?

Answer 34

Y sex chromosome

Question 35

Where do you find the Extra-chromosomal DNA in animals?

Answer 35

Mitochondria

Question 36

What is the pattern of inheritance of mitochondrial DNA?

Answer 36

Matrilineal (only get it from the mothers)

Question 37

Mitochondrial Encephalomyopathy with Lactic Acidosis and Stroke-like episodes (**MELAS**) syndrome is an example of what disease

Answer 37

Mitochondrial disease

Question 38

It is the region of metaphase chromosomes that tie together sister chromatids

Answer 38

centromere

Question 39

It is a region in the end of **linear** chromosomes or eukaryotic chromosomes (non-existent in circular chromosomes/prokaryotic)

Answer 39

telomere | "aglets"

Question 40

- It protects the chromosomes from being destroyed at the tips - play an imp. role in attaching cells during meiosis, spec. in sex cells (attachment of cells to the side nuclei which allows for the pairings of homologous chromosomes) - maintains the information code of the DNA

Answer 40

telomere

Question 41

It is the **ribonucleoprotein enzyme** responsible for **maintenance of the length of telomeres** by addition of **guanine-rich repetitive sequences**

Answer 41

Telomerase

Question 42

What are the stages of the looping of the DNA until it reaches the highly-coiled struct.?

Answer 42

1. DNA Double helix 2. Wrapping og DNA around a **histone octamer** with histone H1 (closer of the loop) 3. Formation of a 3D zigzag structure via histone H1 and other DNA-binding proteins -- It becomes a **nucelosome ("beads on a string")** 4. anchoring of radial loops in the nuclear matrix ---- **radial loop domains** 5. further contraction of radial loops 6. foprmation of a scafold from the nuclear maix and further complication of all radial loops 7. Result: metaphase chromosome

Question 43

Histone proteins is rich in ____, which allows for positive chargers to present and attract the negatively charged DNA around the phosphate region

Answer 43

basic amino acids

Question 44

In the bead on a string is composed of _ subunits of globular proteins plus 1 H1 protein found at the ____ of the bead

Answer 44

8 ; periphery

Question 45

A nucelosome "bead" is composed of what

Answer 45

**8** histone molecules wrapped around by **147** nucleotide pairs of DNA

Question 46

Besides the histone proteins, the chromosome also has helper proteins called _______

Answer 46

anchoring proteins

Question 47

These are two identical strands which are the result of DNA replication

Answer 47

chromatids

Question 48

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

Answer 48

centromere

Question 49

It is a region in the centromere that serves as an attaching point for microtubules and facilitates spidle formation

Answer 49

kinetochore (part of MTOC)

Question 50

It is the whole region in the centromere including the kinetochore where microtubules emerge

Answer 50

Microtubule organizing center (MTOC)

Question 51

The centromere divided the chromosome into:

Answer 51

short arm: *p* (petite) long arm: *q* (queues or *“g”* = grande)

Question 52

# True or False Not all chromosome is nicely divided into *p* and *q* arms

Answer 52

true

Question 53

Molecularly, we can count the number of ____ to identify which is the *p* and *q* arms

Answer 53

bases

Question 54

There are ____ chromosomes that have prominent long and short arms

Answer 54

13

Question 55

# Chromosome Types based on number of centromeres - the only normal kind of chromosome (accdg. kay ian haha, since ito lang yung napapass) - Single centromere - Reliably transmitted from parental to daughter cells

Answer 55

Monocentric

Question 56

# Chromosome Types based on number of centromeres - Lacks centromere - genetically unstable because they cannot be maneuvered properly during cell division and are usually lost (because there is no centromere = no attachment site for microtubules to pull the chromosome w dynein and kinesin towards the pole)

Answer 56

Acentric

Question 57

# Chromosome Types based on number of centromeres - two centromeres - also genetically unstable because it is not transmitted in a predictable fashion

Answer 57

Dicentric

Question 58

Chromosome types are categorized based on what factors?

Answer 58

- numbers of centromeres - centromere position - arms ratio

Question 59

# Chromosome Types based on centromere position - Middle = yielding arms of roughly equal length - Centromere is centrally located - 5 pairs in humans

Answer 59

Metacentric

Question 60

The shape of the **metacentric** chromosome is ________ shape

Answer 60

X shape

Question 61

**1st, 3rd, 16th, 19th** and **20th** are examples what type of chromosome (based on centromere position)

Answer 61

metacentric

Question 62

# Chromosome Types based on centromere position - Off-center centromere; “q” arm is longer - Unequal length of chromosome arms - 13 pairs

Answer 62

Submetacentric

Question 63

# Chromosome Types based on centromere position **2, 4 - 12, 17, 18, X** are examples of what type of chromosome (based on centromere position)

Answer 63

Submetacentric

Question 64

- Acro = peak - centromere severely off-set from centre - Very close to one end; yielding a small short arm - Often associated with small pieces of DNA called **satellites**, encoding rRNA - 5 pairs in humans

Answer 64

Acrocentric

Question 65

In acrocentric type of chromosome, the *p* region is called a ________ region (since it is too short) which contain genetic information

Answer 65

satellite

Question 66

**13 - 15, 21, 22, Y** are examples of what type of chromosome (based on centromere position)

Answer 66

Acrocentric

Question 67

This is a type of centromere found at **end** of chromosome = meaning no *p* arm exists | chromosome not found in humans

Answer 67

telocentric

Question 68

What are the shapes of the following chromosome types: - metacentric - submetacentric - acrocentric

Answer 68

- metacentric = V-shaped - submetacentric = J-shaped - acrocentric = i-shaped

Question 69

It determines the ratio of p and q arms for each chromosome type (L/s) | proposed by Levan et al. (1964)

Answer 69

Arms ratio (r)

Question 70

Telomere is a tandem repeats of the **hexameric sequence** ________

Answer 70

‘TTAGGG’

Question 71

What formation allows the elongation of the telomere and maintains telomere region

Answer 71

lariat formation

Question 72

It prevents abnormal end-to-end fusion of chromosomes

Answer 72

telomere

Question 73

During early meiosis, telomeres play the distinctive function of ________ chromosomes to the **inner nuclear membrane**

Answer 73

anchoring

Question 74

as a consequence of the nuclear membrane polarization, telomeres cluster together into a ________ , which facilitates pairing and recombination of the homologous chromosomes

Answer 74

bouquet configuration

Question 75

This hypothesis proposes that the ends of linear DNA cannot be replicated completely during lagging strand DNA synthesis.

Answer 75

End of Replication Problem Hypothesis

Question 76

Telomerase **replenishes** the ________ and requires **no ATP**

Answer 76

telomere cap

Question 77

In most multicellular eukaryotic organisms, telomerase is active only in:

Answer 77

- germ cells - some stem cells - certain WBC

Question 78

Telomerase can be reactivated and telomeres reset back to an embryonic state by _______

Answer 78

somatic cell nuclear transfer

Question 79

The phenomenon of **limited cellular division** was first observed by ________ , and is now referred to as the **Hayflick limit**

Answer 79

Leonard Hayflick