The Physical Basis of Heredity

Question 1

Chromosome comes from the Greek words for _______________

Answer 1

“chroma”— color and “soma” –body

Question 2

Chromosomes was coined by

Answer 2

Wilhelm von Waldeyer-Hartz

Question 3

Roles of chromosomes

Answer 3

◉ keeps DNA tightly wrapped around
spool-like proteins, called histones
◉ key part of the cell division, ensures DNA is accurately copied and distributed
◉ responsible for containing the instructions that make the offspring unique while still carrying traits from the parent

Question 4

○ a constricted region of a chromosome that separates it into a short arm (p) and a long arm (q)
○ the point of attachment of the kinetochore

Answer 4

Centromere or Primary constriction

Question 5

○ associated with regions were the nucleolus is formed or attached
○ also called _________________
○ knob-like structure is formed at the end called a _____________

Answer 5

Secondary constriction
“Nucleolar Organizing Region”
satellite chromosome (SAT chromosome)

Question 6

○ end of a chromosome
○ made of repetitive sequences of non-coding DNA that protect the chromosome from damage

Answer 6

Telomere

Question 7

Diploid number (2n) –

Answer 7

a condition in which each chromosome exists in pairs

Question 8

Haploid (n) -

Answer 8

a cell or an organism having one member of each pair of homologous chromosomes

Question 9

Homologous chromosomes –

Answer 9

chromosomes or chromosome segments that are identical with respect to their constituent genetic loci and their visible structures

Question 10

Locus –

Answer 10

a place at which a particular gene resides on the genetic or linkage map

Question 11

Genome -

Answer 11

The set of hereditary information encoded in the DNA of an organism, including both the protein-coding and non–protein-coding sequences

Question 12

Involves separation of the genetic material into the two daughter cells

Answer 12

Cellular division

Question 13

Importance of cell division

Answer 13

1. Growth
2. Replenishment
3. Repair and Regeneration
4. Reproduction

Question 14

Which cell has centrosomes, animal cells or plant cells?

Answer 14

Animal cells

Question 15

Stage of Mitosis:

◉ Nuclear membrane disintegrates
◉ Centrioles divide and move apart (animal cells)
◉ Formation of mitotic spindle

Answer 15

Prophase

Question 16

Stage of Mitosis:

◉ Nuclear membrane breaks down
◉ Kinetochores appear at the centromeres
◉ mitotic spindle microtubules attach to kinetochores
◉ centrosomes move toward opposite pole

Answer 16

Prometaphase

Question 17

Stage of Mitosis:

◉ DISJUNCTION
◉ non- kinetochore spindle fibers lengthen, elongating the cell

Answer 17

Anaphase

Question 18

Stage of Mitosis:

◉ Mitotic spindle breaks down

Answer 18

Telophase

Question 19

◉ cleavage furrow (animal cell) and cell plate (plant cell) separate the daughter cells

Answer 19

Cytokinesis

Question 20

What are cell plates made of

Answer 20

Starts with the lining of the Golgi vesicles in the middle of the cell

Question 21

◉ Reduction phase of Meiosis I

Answer 21

Anaphase I

Question 22

◉ short pause between meiosis I and meiosis II
◉ similar to interphase but no replication of the chromosome

Answer 22

Interkinesis

Question 23

◉ Chromosomes double structures

Answer 23

Prophase II

Question 24

◉ Chromosomes uncoil and lengthen

Answer 24

Telophase II

Question 25

Grasshopper (Gesonula punctifrons)
◉ 2n = _______ in males
◉ 2n = _______ in females
◉ XO sex determination

Answer 25

23 (22 autosomes + X)
24 (22 autosomes + XX)

Question 26

Allium cepa assay

Answer 26

An efficient test for chemical screening and in situ monitoring for genotoxicity and cytotoxicity of environmental contaminants

Question 27

Why use onions in the laboratory activity?

Answer 27

➢ Large genome size (>15000 Mbp)
➢ Low number of chromosomes (2n = 16)
➢ A. cepa chromosomes exhibit morphological similarities to mammalian cells

Question 28

Farmer’s fluid composition

Answer 28

1:3 (acetic acid:ethanol)