3.1 GENES

Question 1

GENE

Answer 1

is a heritable factor that controls or influences a specific character consisting of a length of DNA occupying a particular position on chromosome

Question 2

GENE FACTS

Answer 2

Humans: 21,000-23,000 protein coding genes

.Each chromosome contains many different genes often linked in groups.

Question 3

NUMBER OF GENES AND COMPLEXITY OF ORGANISMS

Answer 3

The number of genes in an organism’s genome does not indicate how complicated an organism is, for example dogs have larger genome than human `

Question 4

LOCUS

Answer 4

Each gene occupies a specific location or position on a chromosome called a locus

Question 5

CHROMOSOME NUMBER IN HUMAN DIPLOID CELL

Answer 5

46 chromosomes in a human diploid cell

Question 6

FEMALE GENES

Answer 6

23 pairs including two X chromosomes .

Question 7

MALE GENES

Answer 7

22 pairs plus and X and

Y chromosome

Question 8

ALLELE

Answer 8

one specific form of a gene, differing from other alleles by one or a few bases only and occupying the same gene locus as other alleles of the same gene.

Question 9

NUMBER OF ALLELES AND GENES

Answer 9

There can be two or more alleles of a specific gene depending on the gene. ␣

Question 10

ALLELES AND BLOOD TYPE

Answer 10

The gene that influences human blood type has three different alleles that code for blood types A, B and O.

Question 11

Since each human cell consists of 2 copies of each chromosome

Answer 11

(except X and Y)

there are two copies of each gene.

Question 12

homozygous

Answer 12

two of the same allele

Question 13

heterozygous

Answer 13

two different alleles

Question 14

GENE MUTATION

Answer 14

is a permanent change in the base sequence of DNA. Not all mutation causes disease.

Question 15

BASE CHANGE

Answer 15

When one of the bases is changed, this will cause a change in the mRNA sequence when the DNA is copied during transcription of the gene.

Question 16

SICKLE CELL ANEMIA

Answer 16

a disease that causes red blood cells to form a sickle shape (half-moon). These sickled blood cells cannot carry as much oxygen as normal red blood cells.

Question 17

CONSEQUENCES OF SICKLE CELL ANEMIA

Answer 17

They can cause clots in blood vessels (capillaries) because of their abnormal shape and inflexibility caused by crystallization of the abnormal hemoglobin.

Question 18

BENEFITS OF SICKLE CELL ANEMIA

Answer 18

Sickle-cell anaemia gives immune to malaria, which is a parasite disease carried by mosquitoes.

Malaria cannot infect sickle cells. So people with sickle cell trait are resistance to the disease.

Question 19

LOCATION OF SICKLE CELL ANEMIA

Answer 19

Sickle cell anaemia occurs on chromosome 11, happens ob gene HBB

Question 20

CAUSES OF SICKLE CELL ANEMIA

Answer 20

Sickle cell is caused by a base-substitution when the adenine base in GAG is replaced by a thymine base, changing the triplet to GTG.

Glutamic acid then changed to valine, a negative charged amino acid changed to neutral one.

Amino acid sequence change will then lead to a change in protein structure.

Question 21

GENOME

Answer 21

The whole of the genetic information of an organism

Question 22

HUMAN GENOME

Answer 22

the genome consists of 46 chromosomes plus the mitochondrial DNA

Question 23

PANT GENOME

Answer 23

the genome also consists of chloroplast DNA on top of their chromosomes and mitochondrial DNA

Question 24

PROKARYOTES GENOME

Answer 24

Prokaryotes have a circular chromosome and plasmids in their genome

Question 25

HUMAN GENOME PROJECT

Answer 25

entire base sequence of human genes was sequenced

Scientists can now also predict which sequences do code for protein