4A- DNA, RNA and Protein Syntheis

Question 1

Gene

Answer 1

a section of DNA nucleotide base sequences that codes for a polypeptide protein or functional RNA

Question 2

Eukaryotic DNA storage

Answer 2

1-long, linear DNA associates with histones proteins
2-Histones support DNA
3-DNA coiled up tightly into a compact chromosome so fits in nucleus

Question 3

Prokaryotic DNA Storage

Answer 3

1- carry DNA as chromosomes
2-short and circular DNA molecules
3-DNA not associated with histone proteins
4-condenses to fit into cell via supercoilling

Question 4

Role of histones

Answer 4

1-long, linear DNA associates with Histones proteins to make DNA compact so it can fit into the nucleus
2- supports DNA

Question 5

Gene codes for

Answer 5

1-amino acid base sequence of polypeptide

2-functional RNA - ribosomal RNA +tRNA

Question 6

genome

Answer 6

complete set of genes in a cell

Question 7

Proteome

Answer 7

full range of proteins a cell is able to produce

Question 8

Triplet/codon

Answer 8

series of 3 bases that codes for a specific amino acids

Question 9

Functional RNA

Answer 9

RNA that doesn’t code for a polypeptide chain (NOT mRNA)

-tRNA + rRNA

Question 10

ribosomal RNA

Answer 10

• mRNA binds to ribsosme which is made of RNA so translation occurs
• part of the ribosomes

Question 11

Ribosome made of

Answer 11

• RNA nucleotides

- amino acids

Question 12

role of ribosome in polypeptide synthesis

Answer 12

1. mRNA binds to ribosome
2. Idea of two codons/binding sites;
3. (Allows) tRNA with anticodons to bind/associate;
4. (Catalyses) formation of peptide bond between
   amino acids (held by tRNA molecules);
5. Moves along (mRNA to the next codon)/translocation described

Question 13

why isnt mRNA not a functional RNA

Answer 13

it codes for polypeptide chain

Question 14

Introns

Answer 14

a section of DNA base sequences in a gene that doesn’t code for an amino acid

Question 15

exons

Answer 15

section of DNA base sequences in a gene that codes for an amino acid

Question 16

prokaryotic DNA doesnt have

Answer 16

introns

Question 17

alleles

Answer 17

alternative forms of the same gene

Question 18

why do different alleles code for slightly different versions of the same polypeptide chain

Answer 18

-different sequence of DNA bases

Question 19

Homologous chromosome pair

Answer 19

• both same size
• same genes from each parents
• may have different alleles

Question 20

chromosome

Answer 20

-

Question 21

locus

Answer 21

• position on a chromosome where a particular allele of a gene is found on each chromosome in a pair.
• alleles coding for the same characteristic found at same fixed position

Question 22

Multiple repeats

Answer 22

DNA sequences that repeat outside the gene that don’t code for an amino acid

Question 23

mRNA structure (messenger)

Answer 23

1-carries the genetic code from the DNA in nucleus to the ribosome via leaving nuclear pore
2-single RNA nucleotide strands
3-3 adjacent bases = codons

Question 24

tRNA structure

Answer 24

1-carries amino acids to the ribosomes
2-single RNA polynucleotide strand
3-H bonds between specific base pairs holds folded clover shape
4-anticodon specific base sequence
5-amino acid binding site which requires energy from ATP to bind to tRNA

Question 25

eukaryotic DNA structure

Answer 25

1-non-coding DNA a base sequence of multiple repeats between genes 2-introns non coding DNA base sequences in a gene between exons that is removed via splicing of pre-mRNA 3-DNA Base sequence that codes for amino acids

Question 26

Transcription occurs

Answer 26

-nucleus

Question 27

translation occurs

Answer 27

at the ribsomes in the nucleus

Question 28

Transcription

Answer 28

1-RNA Polymerase attaches to the DNA double helix at the start of the gene. 2-H bonds between the 2 DNA strands in the gene break via DNA Helicase 3-one strand with exposed bases used as template 4-RNA Polymerase lines up free floating RNA nucleotides and complementary base pairing occurs 5-RNA Polymerase joins RNA nucleotides together via condensation reactions forming phosphodiester bonds 6-pre-RNA polynucleotide is a complementary copy of the template strand 7-H bonds between uncoiled DNA strands reform once RNA Polymerase has passed a recoil double helix 8-RNA Polymerase reaches specific DNA triplet Nuceotide base sequence a stop signal 9-stops making Pre-mRNA 11-Splicing -Introns are removed and exons joined together 12-mRNA acts as messenger and moves out of the nucleus into cytoplasm via nuclear pore

Question 29

Prokaryotic DNA Transcription

Answer 29

1-same as transcription of eukaryotes | 2-No splicing as doesn't contain introns so mRNA produced directly from DNA

Question 30

Translation

Answer 30

1-mRNA leaves nucleus via nuclear pore to the ribosomes in the cytoplasm 2-mRNA attaches to a ribosome 3-tRNA molecules carry amino acids to mRNA 4-ATP PROVIDES THE ENERGY NEEDED FOR AMINO ACIDS TO BIND TO tRNA 5-tRNA with anti-codon that's complementary to the first codon on mRNA attaches 6-2nd tRNA molecule attaches to next mRNA codon in the same way 7-2 amino acids attached to tRNA form peptide bond via the ribosomes 8-first tRNA moves away leaving first amino acid behind 9- tRNA molecules move along mRNA to next codon 10-until stop codon is reached 11-ribsomes joins amino acids together in polypeptide chain via condensation reactions which moves away from the ribosome

Question 31

Role of ribosomes in transcription

Answer 31

1-mRNA is read at for translation 2-Once amino acids line up in the correct order it joins amino acids together via condensation reactions forming peptide bonds between each in a polypeptide structure

Question 32

Non-overlapping

Answer 32

base triplets don't share bases so no overlap of bases in a codon

Question 33

degenerate

Answer 33

there are more possible combinations of bases in a triplet than there are amino acids so multiple base triplets can code for the same amino acids

Question 34

Universal

Answer 34

same specific base sequences code for the same amino acids in all organisms

Question 35

stop signals

Answer 35

sequences of bases that stop production of a protein

Question 36

Histones

Answer 36

a protein that associates with DNA so it can condense into chromatin

Question 37

Nucleosome

Answer 37

structural unit of eukaryotic chromosomes with DNA coiled around histone proteins