Exam Revision

Question 1

What do codons indicate?

Answer 1

A particular amino acid

Question 2

Define transcription

Answer 2

The copying of DNA into RNA and then mRNA

Question 3

Define translation

Answer 3

Ribosome reads the mRNA and attaches amino acids together to produce proteins

Question 4

Define mRNA

Answer 4

Messenger RNA
Just like RNA but not in the nucleus
Also has a 5’ cap and a 3’ poly A tail

Question 5

Define intron

Answer 5

Non coding/junk DNA

Is cut out (excised) from RNA in the nucleus

Question 6

Define exon

Answer 6

Coding/important DNA

Spliced together to make mRNA

Question 7

Define Open Reading Frame

Answer 7

The distance between a start codon and a stop codon

Question 8

Define tRNA

Answer 8

Transfer RNAs
They work to decode the messenger RNA
Function at different places at the ribosome

Question 9

Define operon

Answer 9

Unit of linked genes which is thought to regulate other genes responsible for protein synthesis

Question 10

Define promoter

Answer 10

A region of DNA that initiates the transcription of a particular gene

Question 11

Define repressor

Answer 11

A protein that binds to DNA and regulates the expression of genes by decreasing the rate of transcription

Question 12

Define constitutive gene

Answer 12

A gene that is transcribed continually opposed to a facultative gene

Question 13

Define facultative gene

Answer 13

A gene that is transcribed only when needed as opposed to a constitutive gene

Question 14

Define central dogma

Answer 14

Transcription and translation

Question 15

Define splicing

Answer 15

The joining of exams

Question 16

Define a ribosome

Answer 16

A particle of a large and small subunit of ribosomal RNA and protein that bind mRNA and tRNA together to synthesise proteins

Question 17

Define a frame shift mutation

Answer 17

Addition or deletion of a base pair or base pairs in the DNA of a gene
This means that the genetic code is translated in an unnatural reading frame from the position of the mutation to the end of the gene

Question 18

What are the 3 stop codons?

What is the start codon?

Answer 18

Stop: UAA, UGG, UGA
Start: AUG

Question 19

How many chromosomes do humans have?

Answer 19

46 grouped into 23 pairs

Question 20

What is a somatic cell?

Answer 20

Diploid. Not a sex cell. Has 23 PAIRS of chromosomes

Question 21

What is a sex cell?

Answer 21

Haploid. 23 SINGLE chromosomes.

Question 22

What are the four types of lipids

Answer 22

Fats
Phospholipids
Waxes 
Steroids
All consist of a phosphate head attached to a glycerol molecule attached to two fatty acid tails

Question 23

Describe the primary structure of proteins

Answer 23

The sequence of amino acids in a chain

Question 24

Describe the secondary structure of proteins

Answer 24

Hydrogen bonding between the polypeptide backbone

Forms alpha helices and beta pleated sheets

Question 25

Describe the tertiary structure of proteins

Answer 25

Bonding between side chains of alpha helices and beta pleated sheets

Question 26

Describe the quaternary structure of proteins

Answer 26

A protein consisting of more than one amino acid chain

Question 27

What’s another name for amino acid chains?

Answer 27

Polypeptides

Question 28

The anticodon of a particular tRNA is …

Answer 28

Complementary to the corresponding mRNA codon

Question 29

What is rRNA

Answer 29

Ribosomal RNA

Question 30

Define genotype

Answer 30

The particular alleles at specified loci present in an organism

Question 31

Define phenotype

Answer 31

The observable characteristics of an organism due to the expression of a genotype as well as the effect of the environment

Question 32

Define allele

Answer 32

Alternate forms of a gene (or nucleotide sequence) that control the same character

Question 33

Define locus

Answer 33

The specific position of a gene on a chromosome

Question 34

Define homologous chromosomes

Answer 34

Similar but different too

Same loci but not necessarily the same alleles