L2

Question 1

true or false; the evolutionary complexity of an organism is not related to their chromosome number and chromosome size

Answer 1

true

Question 2

true or false; eukaryotes have much more DNA than they need simply for their genes

Answer 2

true

Question 3

Give examples of a specialized regions in the chromosome that is used for the chromosome’s identification

Answer 3

centromere

nucleolar organizers

Question 4

what is the centromere responsible for

Answer 4

for the attachment and movement of the chromosome on the spindle; the primary constriction in the chromosome

Question 5

what is the position of the centromere relative to

Answer 5

relative to the chromosome ends

Question 6

what is the positioning of the centromere used for

Answer 6

used to classify and identify chromosomes

Question 7

what are the 3 names of the different types of chromosomes based of their centromere location

Answer 7

metacentric
acrocentric
telocentric

Question 8

what are nucleolar organizers

Answer 8

sites of the ribosomal RNA genes and like the centromere their position is variable along the chromosome arm so they can be used for identification purposes

Question 9

what are telomeres

Answer 9

are found at the ends of the chromosome, play an important role in DNA replication, and in ‘sealing’ the ends of the chromosomes

Question 10

what do you call the densely staining regions of the chromosomes

Answer 10

heterochromatin

Question 11

what do you call the less densely staining regions of the chromosome

Answer 11

euchromatin

Question 12

Where can you find polytene chromosomes

Answer 12

salivary glands of many flies

Question 13

what pattern do polytene chromosomes exhibit

Answer 13

show transverse bands due to the different staining; useful for chromosome identification

Question 14

what do you call the proteins that package DNA

Answer 14

histones

Question 15

briefly describe how DNA is packaged

Answer 15

packaged with the aid of histones and a complex order of coiling into structures that can readily be moved around the cell

Question 16

what is nucleosome

Answer 16

basic unit of a chromatin

Question 17

what do you call the linker histone

Answer 17

H1

Question 18

what is n

Answer 18

haploid set, single set

Question 19

true or false, most fungi and algae have only one set of chromosomes

Answer 19

true, therefore they are haploid

Question 20

true or false, most plants and animals have two sets of chromosomes in their body cells

Answer 20

true, therefore they are diploid (2n)

Question 21

what is the lowest haploid number and which species is this from

Answer 21

ant species, n=1

Question 22

what species has the highest amount of haploid number, and what is that haploid number

Answer 22

fern, n=728

Question 23

how many gametes can an organism produce

Answer 23

2^n

Question 24

why can’t the fern sexually reproduce, rather reproduce aesexually

Answer 24

due its large number of gametes

Question 25

true or false, the number of chromosomes a species has is not related to its genome size

Answer 25

true

Question 26

how many chromosomes do humans have

Answer 26

46 chromosomes

Question 27

how many autosome pairs do humans have

Answer 27

22

Question 28

how many sex chromosome pairs do human have

Answer 28

1

Question 29

what is the largest chromosome in humans and what is the smallest, respectively

Answer 29

1 and 21

Question 30

define karyotype

Answer 30

karyotype is the morphology of ALL the chromosomes at mitotic metaphase

Question 31

how is karyotype organized

Answer 31

chromosomes organized in pairs and, from largest to smallest

Question 32

true or false, each functional chromosome has a centromere (where spindle fibres attach) and two telomeres (stablize the chromosome)

Answer 32

true

Question 33

what is the most important feature of the chromosome

Answer 33

centromere position

Question 34

What does it mean by telocentric

Answer 34

centromere at one end; when the chromosome moves towards one pole of the cell during anaphase of cell div., it appears as a simple rod, i shaped

Question 35

Acrocentric

Answer 35

centromere off centre; during anaphase it appears as a J

Question 36

metacentric

Answer 36

has its centromere in the middle; during anaphase it appears as a V

Question 37

where are telomeres located

Answer 37

at the ends of chromosomes

Question 38

true or false, there is no visible structure that distinguishes the telomeres from the rest of the chromosome

Answer 38

true

Question 39

What characterizes telomeres

Answer 39

tandem repeats

Question 40

what is the tandem repeat in the ciliate Tetrahymena telomeres

Answer 40

TTGGGG

Question 41

what is the tandem repeat in human telomeres

Answer 41

TTAGGG

Question 42

what is the kinetochore

Answer 42

protein which spindle fibres attach

Question 43

What is a nucleoli

Answer 43

are organelles within the nucleus that contain ribosomal RNA and components of ribsomes

Question 44

where does the nucleoli reside

Answer 44

resides next to a slight constriction in the chromosome called NO (nucleolar organizer)

Question 45

what do NO's look like

Answer 45

contrictions, called secondary constrictions

Question 46

true or false, NO's are located at different positions on the chromosome

Answer 46

true, like the centromeres

Question 47

true or false, ribosomal genes are tandem repeats

Answer 47

true

Question 48

how many ribosomal repeats does the human NO have

Answer 48

250 copies

Question 49

what do you call a protein and DNA complex

Answer 49

chromatin

Question 50

true or false, chromatin is not uniformly distributed along a whole length of the chromosome

Answer 50

true

Question 51

What is euchromatin

Answer 51

is a loosely packed form of chromatin, that is rich in genes it has high recombination frequency and stains weakly in interphase

Question 52

what is heterochromatin

Answer 52

tightly packed or coiled chromatin a region with a few genes lower recombination frequency stains densely at interphase

Question 53

what are the two things that heterochromatin can be

Answer 53

facultative or constitutive

Question 54

what is constitutive heterochromatin

Answer 54

a permanent feature of a specific chromosome location, gene poor and can inactivate genes

Question 55

what is facultative heterochromatin

Answer 55

is sometimes but not always found in a particular chromosome location; normal gene content, can be switched on and off, characteristic of sex chromosomes

Question 56

what are knobs

Answer 56

conspicuous heterochromatin regions

Question 57

what is consistent and specific to individual chromosomes

Answer 57

position and size of the chromosome bands

Question 58

what is common DNA stain

Answer 58

Giemsa; critical factor is chromatin packing density

Question 59

what are polytene chromosomes

Answer 59

Giant chromosomes that are found in certain tissues of Drosophila and other organism

Question 60

how do polytene chromosomes arise

Answer 60

arise from repeated rounds of DNA replication WITHOUT CELL DIVISION; there are thousands of DNA lying side by side

Question 61

what portion of the genome becomes polytene

Answer 61

the euchromatic region

Question 62

true or false, drosophila has four pairs of chromosomes and the euchromatic portion of the genome becomes polytene while the heterochromatin coalesces to form a chromocenter

Answer 62

true

Question 63

what is a chromosomal puff

Answer 63

regions of relaxed chromatin where active transcription is taking place

Question 64

why is the human genome packed

Answer 64

so that it can be moved during cell division, brought about by coiling of the DNA around protein histone cores (nucleosomes) and these are then organized into a further series of coils (solenoids)