Topic four

Question 1

Describe DNA in prokaryotic cells

Answer 1

Short, circular, and not associated with proteins

Question 2

Describe DNA in eukaryotic cells

Answer 2

-Long, linear, and associated with histone proteins
-DNA and its associated proteins coil to form a chromosome

Question 3

Describe the DNA found in mitochondria and chloroplasts

Answer 3

-Similar to prokaryotic DNA
-Short, circular, and not associated with proteins

Question 4

Genetic code: universal

Answer 4

The genetic code is the same in all organisms

Question 5

Genetic gode: degenerate

Answer 5

Multiple codons can code for the same amino acid

Question 6

Genetic code: non-overlapping

Answer 6

Each base only appears in one triplet base sequence

Question 7

Genome

Answer 7

The complete set of genes in a cell

Question 8

Proteome

Answer 8

The full range of proteins that a cell is able to produce

Question 9

Describe the structure of tRNA

Answer 9

-Strand of RNA folded into a clover shape
-One end attaches to a specific amino acid
-The other end has an anti-codon that binds to a complementary section of mRNA

Question 10

Describe transcription of mRNA

Answer 10

-DNA helicase ‘unzips’ the H bonds, only one template strand is used
-RNA polymerase attaches to template and free RNA nucleotides align by complementary base pairing (A-U, C-G)
-RNA polymerase synthesises phosphodiester bonds between adjacent nucleotides and detaches when it reaches a stop signal
-In eukaryotes, pre-mRNA is formed, som splicing occurs to remove introns, forming mRNA