B1.2 What Happens In Cells

Question 1

Structure of DNA

Answer 1

2 strands joined by complementary bases
Adenine and Thymine, Cytosine and Guanine
Twisted in double helix
It is a polymer made of nucleotides which is composed of deoxyribose, a phosphate and a base

Question 2

Transcription

Answer 2

DNA unzips so strands are separated
One strand acts as template
Free nucleotides attach to complementary bases forming mRNA
There is no Thymine in mRNA so Uracil is made instead
mRNA detached and DNA zips back up

Question 3

Translation

Answer 3

mRNA attaches to ribosome in cytoplasm
Ribosome reads bases in codons
Each codon produces a specific amino acid
Ribosome continues to read codons and form amino acids
Amino acids link to form specific protein

Question 4

What are enzymes

Answer 4

They are proteins that act as biological catalysts

Question 5

What do proteins do

Answer 5

Synthesise new molecules
Break down big molecules
Join together small molecules

Question 6

Active site

Answer 6

Active site of an enzyme is highly specific, if active site is damaged or changes, enzyme can’t bind to substrate so it denatures