Unit 3: DNA and Enzymes

Question 1

Enzymatic reactions

Answer 1

Reactants are substrates and the result of the catalyzation are products

Question 2

What is an enzyme?

Answer 2

Biological catalyst, speeds up chemical reactions

Question 3

How do enzymes function?

Answer 3

They lower activation energy (threshold)

Question 4

How do enzymes reduce activation energy?

Answer 4

Substrates bind to active sites on enzymes (lock and key) forming enzyme-substrate complexes

enzyme changes shape to fit substrate and then they separate, returning to original shape to accept a new substrate

Question 5

DNA and RNA main differences

Answer 5

Pentose sugar (ribose or deoxyribose)
Phosphate group
Nitrogenous base
T - dna only
U - rna only

single vs double stranded

sugar phosphate backbone held by nitrogenous bases using hydrogen bonds

Question 6

Transcription

Answer 6

Begins in nucleus, DNA is unzipped by DNA helicase. RNA polymerase attaches to the DNA to be transcribed. RNA polymerase adds base pairs, creating mRNA. mRNA is further processed and DNA is zipped up before leaving nucleus.

Question 7

Translation

Answer 7

Occurs at the ribosome.

mRNA is read, the codons (3 nucleotide sequence) are read and translated by tRNA, attaching the matching amino acids. This process stops when the STOP codon is read

Question 8

Malignant vs Benign

Answer 8

Benign: abnormal cell growth that is irregular but not harmful

Malignant: Benign tumours that undergo mutation and become harmful

Question 9

Cancer cell characteristics:

Answer 9

generally unstable
do not respond to apoptosis signals
do not regulate cell cycle
can survive and proliferate elsewhere in the body

Question 10

Metastasis and angiogenesis

Answer 10

Metastasis is the spread of cancer to other parts of the body

Angiogenesis is when tumours increase their blood supply by forming new blood vessels