Chromosomes

Question 1

What is the genome of prokaryotes composed of?

Answer 1

a single double stranded molecule

Question 2

What is the genome of eukaryotes composed of?

Answer 2

several double stranded DNA molecules

Question 3

What is a haploid cell?

Answer 3

A cell which contains 1 copy/chromosome

Question 4

What are genes?

Answer 4

They are a part of a DNA which is a part of a chromosome which is located int he nucleus of the cell. Genes determine specific characteristics by coding for specific proteins

Question 5

What are homologous chromosomes?

Answer 5

A pair of homologous chromosome codes for the same gene (hair colour) but the alleles may differ

Question 6

What is an allele?

Answer 6

Different variation of the same gene

Question 7

What are the female sex chromosomes?

Answer 7

XX

Question 8

What are the male chromosomes?

Answer 8

XY

Question 9

What is the DNA histone complex called?

Answer 9

Chromatin

Question 10

What are autosome chromosomes and how many do we have in a human chromosome?

Answer 10

They are body chromosomes (not sex chromosomes) and we have 22/chrom.

Question 11

What is the abnormality in the human karyotype with chromosomes 21 and 22.

Answer 11

Chromosomes 22 is actually longer than chromosome 21. In a karyotype, chromosomes are placed from 1 to 23 in increasing size.

Question 12

What causes Down syndrome or trisomy 21

Answer 12

Individuals have 3 copies of chromosome 21 while the average human has 2.

Question 13

What characterizes Turner Syndrome?

Answer 13

Women who have a single X chromosome instead of 2

Question 14

What characterizes Jacobsen syndrome?

Answer 14

A part of chromosome 11 is deleted

Question 15

What are chromosome number disorders caused by?

Answer 15

They are caused by disjunction which is when homologous chromosome pairs or sister chromatids fail to separate during meiosis. The risk of non-disjunction increases when the parents’ age increases.

Question 16

What are gametes?

Answer 16

haploid cells that contain 23 chromosomes

Question 17

What is aneuploidy?

Answer 17

individuals with errors in the number of chromosomes

Question 18

What is monosomy

Answer 18

Individuals who have 1 chromosome less (2n-1=45)

Question 19

What is trisomy?

Answer 19

Individuals who have 1 extra chromosome (2n+1=47)

Question 20

What is nullisomy?

Answer 20

Individuals who have 2chrom less (2n-2=44)

Question 21

What is tetrasomy?

Answer 21

Individuals who have 2 extra chromosome (2n+2=48)

Question 22

What is polyploidy?

Answer 22

Individuals with more chromosome SETS

**Very common in the plant kingdom

Question 23

What happens if a woman has 3X chromosomes?

Answer 23

She is still considered a woman but experiences delays and reduced fertility

Question 24

What happens if you have XXY sex chromosomes? What sex are you?

Answer 24

This is referred to as Klinefelter syndrome. You are a make who has small testicles, enlarged breasts and reduced body hair

Question 25

What happened to the other X chromosomes if you have a surplus? Let’s say you have 3X instead of 2…

Answer 25

Every extra X chrom except for 1 will be inactive

Question 26

Describe the DNA molecules of a single stranded chromosome.

Answer 26

The DNA molecules are double stranded

Question 27

Describe the DNA molecules of a double stranded DNA chromosome.

Answer 27

They are single stranded

Question 28

What is the telomere?

Answer 28

It is the end points on a chromosome

Question 29

What is the centromere?

Answer 29

It is the point at which the chromosome bunches giving it the look of two ovals

Question 30

How many chromatid are present in a single stranded chromosome?

Answer 30

0

Question 31

How many chromatids are present in a double stranded chromosome?

Answer 31

2

Question 32

What is chromatin

Answer 32

DNA + protein

Question 33

What are double stranded chromosomes composed of?

Answer 33

2 identical molecules of DNA

Question 34

Is our karyotype composed of double stranded or single stranded chromosomes?

Answer 34

Double

Question 35

Describe a haploid cell.

Answer 35

1n (1chromosome/type). the chromosomes are single stranded.

Question 36

Describe a diploid cell

Answer 36

2n (2chromosomes/type). chromosomes are double stranded

Question 37

What are gametes ?

Answer 37

Gametes are haploid cells and include sperm and ova. Once they come together to form a zygote, they form a diploid cell which will tern into a human being with 2n cells.

Question 38

Describe all the possible changes in chromosome structure that can happen.

Answer 38

1) Inversion: When 2 genes in the sequence get inverted
2) translocation: A new piece of chromosome (it detached from its former chromosome) is added to your existing chromosome ** causes leukaemia
3) Deletion: Removal of a piece of chromosome/gene
4) Duplication: When a gene is duplicated and added to the chromosome. This is what causes evolution in human beings

Question 39

List the genome, genes, DNA.. in order of increasing size (what is part of what)

Answer 39

Cell, nucleus, genome, chromosomes, DNA, genes (a segment of DNA) , nucleotides (ATCG)

Question 40

What does n represent?

Answer 40

Number of unique chromosomes within a cell. For example, a human cell contains 46 chromosomes however, it has 23 unique chromosomes and 2 copies of each. Therefore 2n = 46 for humans

Question 41

What are homologous chromosomes?

Answer 41

maternal and paternal copies of the same chromosome

Question 42

What is a chromosome made of?

Answer 42

Condensed chromatin (DNA + histones)