Week 3 - Eukaryotic and prokaryotic genome.

Question 1

Genetic code

Answer 1

Genetic code : set of DNA and RNA = determines aminoacid sequence when synthesizing proteins for an organism.

Biochemical basis for hereditary
Hereditary = ärftlighet
nearly universal in all organism.

Set of 64 codons (building block of 3 nucleotides) - correspondant to
the 20 aminoacids- protein synthesis and + signals for starting and stopping proteins. 4x4x4 nt = 64

Codes are nonoverlapping
One code = 1 aminoacid.
not meaning of 2 or 3.

Each code is dedicated to 1 aminoacid. Code is triplets of nucleotides.

Question 2

Explain how you should read this image

Answer 2

By not reading it!

Question 3

Start codon?

Stop codon?

Other aminoacids are specified by more than one codon…

Answer 3

Start codon AUG - codes for methosine

Stop codon are UAA, UAG, UGA. They encode no aminoacid

Usually difference in 3rd part, called degenerate code

Question 4

What to understand from this picture

Answer 4

Different sequences for same protein.

Question 5

Why is there sometimes improper use of the term genetic code

Answer 5

Found fossils with their “genetic code” but should be found genome

Question 6

What information to extract from this slide?

Answer 6

Nearly universal means not, difference in e.g. stop codon for different species etc.

Question 7

Definition of the gene in plain terms and in molecular terms

Short answer to the terms the parts of the gene?

What do genes encode?

Answer 7

Fundamental, physical and functional unit of heredity

In molecular terms

a gene is a chromosomal DNA sequence
required for synthesis of functional protein or RNA molecule

A gene has
- coding regions a.k.a exons
- transcription- control regions
- introns

Majority of genes encode proteins, some encode different types of RNA (e.g tRNA and rRNA

Question 8

Draw an overview of the gene structure transcription

No acces to internet? Draw a mental image homie dont be lazy

Answer 8

Question 9

Promoter region

Answer 9

Located at 5’ end

• has sequences responsible for proper initation of transcription

Question 10

What exists in the 5’ end

What does numbers on the sequence mean? e.g -25

Answer 10

Several DNA elements, whose sequence is conserved among different genes
e.g.
- CpG regions
- TATA box
- CpG island
- Locus control region

Conserved meaning = they barely havent changed evolutionary, find in many parts in all sort of species. High similarity of regulatory sequences. Important evoloutionary throughout time.

Numbers meaning: Everything downstream after start of transcription is positive and everything before is negative

Question 11

TATA box
Located?

Answer 11

25-30 bp upstream from transcription (before yani)

Important: determine start of transcription

1/4 of human genes contain TATA box regulatory sequence
Tissue-specific genes
More robust genes dont have these?

Question 12

Downstream and upstream in genes meaning?