RNA synthesis

Question 1

Define Transcription (1)

Answer 1

synthesis of mRNA transcript from DNA, same language – nucleic acid.

Question 2

Define Translation (1)

Answer 2

protein production from mRNA transcript, different languages – nucleic acid to protein

Question 3

How many nucleotides are there? (1)

Answer 3

3.2 x10^9

Question 4

How many pairs of chromosomes have we got, and what are the two types? (3)

Answer 4

23 chromosomes- Autosomes 22 pairs and 1 pair of sex chromosomes

Question 5

Define Autosomal linkage

Answer 5

Genes present on the same non-sex chromosomes.

Question 6

Define sex-linked genes

Answer 6

Genes carried on the same sex chromosomes.

Question 7

Purpose of a chromosome?

Answer 7

Chromosomes serve the purpose of carrying genes

Question 8

What is the function of the centromere?

Answer 8

keeping chromosomes attached to the mitotic spindle during mitosis so that each new daughter cell has one copy.

Question 9

Describe Telomeres

Answer 9

Located at the end of chromosomes.

Very relative DNA, 6 base pair repeats, protect the end of the chromosome ensuing genetic code is not destroyed or lost.

Prevents against strands linkages so that chromosomes don’t join together.

Question 10

Describe Genes on a chromosome

Answer 10

20,000 genes

Gene – unit of heredity, contains instructions for an organism’s phenotype. DNA segment containing instructions for making a particular product, including the regulatory elements. It is not just a gene that codes for protein.

Intergenic region (between the genes) is composed of most of the DNA we carry, not much DNA is coding for proteins. They control how genes are expressed in a cell – we only just beginning to understand what they are.

An arrow on the length of a gene always represents where transcription starts.

Question 11

What is an exon?

Answer 11

regions of coding DNA or RNA. Exons are expressed.

Question 12

What is an intron?

Answer 12

regions of non-coding DNA or RNA.

Question 13

What is the purpose of the 5’ and 3’ UTRS?

Answer 13

5’ - Regulation of translation

3’ - mRNA stability and miRNA binding

Question 14

What are the different human RNA polymerases?

Answer 14

Type of polymerase Genes transcribed
RNA polymerase 1 Most ribosomal RNA (rRNA)
RNA polymerase 2 Protein-coding, microRNA (miRNA), non-coding RNA
RNA polymerase 3 Transfer RNA (tRNA), 5S rRNA, other small RNAs.

Question 15

RNA synthesis

Answer 15

Dozens of polymerases work on the same gene

Many transcripts are produced from the same gene

Relatively quick 1.25-1.74kb (kilobase) per minute.

Question 16

Transcription factors

Answer 16

Proteins required to initiate and regulate transcription in eukaryotes.

Assemble on the promotor region to help RNA polymerase 2 to bind.

They also pull apart DNA helix and expose template strand.

Question 17

Why cap and polyadenylate?

Answer 17

1. Stability
2. Transport out of the nucleus
3. Integrity prior to translation

Question 18

Define Homologous chromosomes

Answer 18

chromosome pairs (one from each parent) that are similar in length, gene position, and centromere location. The position of the genes on each homologous chromosome is the same, however, the genes may contain different alleles. Paternal homolog is inherited from the father and maternal homolog is inherited from the mother

Question 19

How is RNA exported from the nucleus

Answer 19

SPECIFIC ADAPTOR PROTEINS
POLY A BINDING FACTOR
EXON JUNCTION COMPLEX
CAP BINDING PROTEIN

Question 20

Describe gene-specific regulation of transcription

Answer 20

There are additional sequences upstream needed for gene-specific regulation of transcription (e.g enhancers and proximal control elements.)