CB3- Meiosis, DNA, Alleles and Genes, Variation, tRNA and mRNA

Question 1

Meiosis

Answer 1

A type of cell division that produces gametes

Question 2

Gamete

Answer 2

Sperm and eggs in animals, pollen and egg cells in plants. Contains half of the genetic material.
There are 23 gametes in a chromosome.
Gametes contain half the chromosomes contained in normal diploid cells of the body.

Question 3

Fertilisation

Answer 3

A male and female gamete join together and the 2 nuclei fuse. When this happens, the new cell (zygote) has a full set of chromosomes.

Question 4

Zygote

Answer 4

A diploid cell resulting from the fusion of the 2 haploid gametes

Question 5

Diploid

Answer 5

(Of a cell in the nucleus) containing 2 complete sets of chromosomes, one from each parent.

Question 6

Haploid

Answer 6

(Of a cell in the nucleus) having a single set of chromosomes.

Question 7

Daughter cell

Answer 7

A cell formed by the division or budding (asexual reproduction) of another

Question 8

DNA

Answer 8

Deoxyribose acid, the genetic material of the cell (material that makes up genes)

Question 9

Genes

Answer 9

A short section of DNA that codes for a specific protein.

Question 10

Chromosomes

Answer 10

Many genes are folded into a large structure called chromosomes. Or a large structure in the nucleus made of DNA

Question 11

Proteins/ Amino Acids

Answer 11

Amino acids are the building blocks of proteins

Question 12

How many chromosomes are there in the nucleus?

Answer 12

23 pairs

46 chromosomes

Question 13

Bases

Answer 13

In DNA there are 4 bases: adenine (A) and guanine (G), then cytosine (C) and thymine (T). In RNA T is replaced with U (uracil)

Question 14

Double Helix

Answer 14

DNA is made of 2 strands, wound around each other to form a double helix (DNA’s shape).

Question 15

Nucleotide

Answer 15

Consists of a sugar (deoxyribose), phosphate and 1 of the 4 bases.
Makes up the backbone of DNA.

Question 16

Hydrogen bonds

Answer 16

Holds the 2 complimentary bases together.
G and A have 3 bonds
T and C have 2 bonds

Question 17

Allele

Answer 17

A version of a gene

Question 18

Gene

Answer 18

A short section of DNA that codes for a specific protein.

Question 19

Dominant

Answer 19

An allele that is always expressed

Question 20

Recessive

Answer 20

An allele that is not expressed if a dominant is present.

Question 21

Homozygous

Answer 21

When 2 copies of the same allele are present

Question 22

Heterozygous

Answer 22

When 2 different alleles are present.

Question 23

Phenotype

Answer 23

The characteristics that are expressed by those alleles.

Question 24

Genotype

Answer 24

The alleles that are present in the genome.

Question 25

Genome

Answer 25

Contains all of the information needed to make that organism. In humans, the genome is all 46 chromosomes in the nucleus.