3.2 CHROMOSOMES

Question 1

PROKARYOTES

Answer 1

Prokaryotes have circular DNA without association of protein.

There is one copy of each gene except when the cell and its DNA are replicating

Question 2

PLASMID IN PROKARYOTES

Answer 2

Plasmids are small separate (usually circular) DNA molecules located in some
prokaryotic cells

Plasmids are also naked (not associated with proteins) and are not needed for daily life processes in the cell.

Question 3

PLASMID GENES

Answer 3

The genes in plasmids are often associated with antibiotic resistant and can
be transferred from one bacterial cell to another. ␣

Question 4

USE OF PLASMID

Answer 4

Plasmids are readily used by scientists to artificially transfer genes from one
species to another (ie. Gene for human insulin)

Question 5

PLASMID FEATURES (6)

Answer 5

Naked DNA without association of protein such as histone

Small circular ring of DNA

Not responsible for normal life process

Contain survival characteristics, e.g. antibiotic resistance

Can be passed on between bacteria

Can be incorporated into nucleoid chromosomes (save permanently)

Question 6

EUKARYOTIC CHROMOSOMES

Answer 6

Eukaryotic chromosomes are linear and are made up of DNA and histone proteins.

Question 7

HISTONES

Answer 7

Histones are globular shaped protein in which the DNA is wrapped around.

Question 8

VARIATION OF EUKARYOTIC LINEAR CHROMOSOMES

Answer 8

length, centromere location and genes contained

Question 9

NUMBER OF CHROMOSOMES IN HUMAN

Answer 9

23

Question 10

NUMBER OF AUTOSOMES IN HUMANS

Answer 10

22

Question 11

23RD PAIR

Answer 11

SEX CHROMOSOMES

Question 12

WHAT DOES EACH CHROMOSOME CARRY?

Answer 12

specific sequence of genes along the linear DNA molecule

Question 13

CHROMOSOME NUMBER AKA

Answer 13

‘N’ number

Question 14

NORMAL CELLS CONTAIN

Answer 14

diploid nucleus
2N
two pairs of homologous chromosomes

Question 15

SEX CELLS CONTAIN

Answer 15

haploid nucleus
N
one pair of homologous chromosome

Question 16

IMPORTANT CHARACTERISTIC OF A SPECIES

Answer 16

chromosome number

Question 17

HOMOLOGOUS CHROMOSOMES

Answer 17

chromosomes within each cell that carry the same genes at the same loci

They have the same structure and size

Question 18

HOMOLOGOUS CHROMOSOME ORIGIN

Answer 18

One chromosome came from an individual’s mother and one from the father

Question 19

WHAT DO HOMOLOGOUS CHROMOSOMES DO DURING MEIOSIS?

Answer 19

These chromosomes pair up during meiosis

Question 20

EVEN THOUGH HOMOLOGOUS CHROMOSOMES CARRY THE SAME GENES…

Answer 20

they could have different alleles

Question 21

SEX CHROMOSOMES

Answer 21

The X and Y chromosome determine the sex of an individual

Question 22

X CHROMOSOME

Answer 22

The X chromosome is quite large in comparison to the Y chromosome
and has a centromere that is located near the centre or middle of the
chromosome

Question 23

Y CHROMOSOME

Answer 23

The Y chromosome is relatively small with its centromere located near
the end of the chromosome

Question 24

SEDX DETERMINATION?

Answer 24

If an individual has two X chromosomes they will be a female and if
they have an X and a Y chromosome they will be a male

Question 25

NOT SEX CHROMOSOMES

Answer 25

AUTOSOMES

Question 26

AUTOSOMES

Answer 26

do not affect the

sex of an individual

Question 27

SRY

Answer 27

SRY genes on Y chromosomes lead to male development

Question 28

KARYOGRAM

Answer 28

we distinguish sex, it shows the chromosomes of

an organism in homologous pairs of decreasing length