Topic 12 - DNA, Protein Synthesis, and Cell Division

Question 1

Asexual reproduction

Answer 1

When offspring is produced from one parent through the mitosis of body cells

Question 2

Gamete

Answer 2

A sex cell

Question 3

Mitosis

Answer 3

A type of cell division that happens in somatic cells. The two genetically identical cells produced are diploid.

Mitosis is used for growth, repair, and asexual reproduction

1. Prophase - chromosomes become visible and the nucleus disappears
2. Metaphase - chromosomes line up at the cell equator
3. Anaphase - chromosomes are pulled to the poles of the cell by spindles
4. Telophase - the chromosomes arrive at the poles
5. Cytokinesis - nucleus reforms as cells split into two

Question 4

Meiosis

Answer 4

A type of cell division that results in genetically unique gametes. A total of four haploid daughter cells will be produced.

• Each chromosome makes identical copies of itself (forming X-shaped chromosomes)
• First division: chromosomes pair up along the equator, recombination occurs and then cell fibres will pull the pairs apart, each new cell will have one of each recombinant chromosome pair
• Second division: chromosomes will line up along the centre of the cell, cell fibres will pull them apart (as with mitosis)

Question 5

Diploid

Answer 5

Cells that have the full number of chromosomes in homologous pairs
(body cells)

Question 6

Haploid

Answer 6

Cells that have half the normal number of chromosomes (gametes)

Question 7

Fertilisation

Answer 7

The fusing of the nucleus from a male gamete with the nucleus from a female gamete

Question 8

Zygote

Answer 8

A fertilised egg

Question 9

Chromosomes

Answer 9

A strand of DNA found in the nucleus of a cell

Question 10

Parent cell

Answer 10

A cell that divides to produce daughter cells

Question 11

Daughter cell

Answer 11

A cell that is produced after a parent cell divides

Question 12

DNA replication

Answer 12

DNA producing an identical copy of itself

Question 13

Clone

Answer 13

A genetically identical organism

Question 14

Identical twins

Answer 14

Genetically identical twins formed from the same zygote

Question 15

DNA

Answer 15

The chemical from which chromosomes are made

Question 16

Cell

Answer 16

The basic building block of a living organism

Question 17

Gene

Answer 17

A section of DNA coding for a particular protein

Question 18

Chromosome

Answer 18

Thread-like structures holding genes

Question 19

Nucleus

Answer 19

The part of a cell that contains genetic information

Question 20

Codon

Answer 20

Three nucleobases that code for one amino acid

Question 21

Nucleotide structure

Answer 21

phosphate (oval) - sugar (pentagon) - nitrogen-containing base (rectangle)

Question 22

Transcription

Answer 22

A process that happens in the nucleus and creates mRNA

1. The DNA strands unzip. One strand is used as a template
2. RNA polymerase binds to a region of DNA just before the gene. This starts the process of transcription.
3. RNA polymerase moves along the DNA and uses the template strand to make mRNA by bringing in the complementary base and joining these together in a single strand
4. Once made, the mRNA molecule will move out of the nucleus towards a ribosome

Question 23

mRNA

Answer 23

Carry protein information from the DNA in a cell’s nucleus to the cell’s cytoplasm. It forms the complementary code to the DNA’s original code

Question 24

RNA polymerase

Answer 24

An enzyme that synthesises (builds) RNA by following a strand of DNA and joining bases together

Question 25

tRNA

Answer 25

brings amino acids together

Question 26

Translation

Answer 26

a process that builds a chain of amino acids 1. tRNA molecules have amino acid attached to them 2. The other end of the tRNA molecule has an anticodon. If this anticodon is complementary to the codon on the mRNA it will pair up, bringing the amino acid with it. 3. The order with which the amino acids are brought in depends on the order of bases on the mRNA. 4. The amino acids will be joined together by the ribosome to form a protein

Question 27

Mutations

Answer 27

A rare, random change in the sequence of bases in an organism's DNA.

Question 28

Mutagen

Answer 28

A physical or chemical agent that permanently changes genetic material