nucleic acid, dna, rna

Question 1

name and describe the 4 genetic processes in macromolecular synthesis

Answer 1

1. replication- DNA synthesis from existing DNA
2. transcription- RNA synthesis from DNA
3. translation- protein synthesis from decoding RNA
4. RNA modification- modify RNA in nucleus

Question 2

describe the structure of a nucleotide

Answer 2

pentose sugar- deoxyribose, ribose
phosphate
nitrogenous base- adenine, thymine, uracil, guanine, cytosine
sugar phosphate backbone is formed from phosphodiester bonds, hydrogen bonding occurs between bases, always from 5’ to 3’

Question 3

what are purines and pyrimidines

Answer 3

purines have 2 rings and pyrimidines have 1 ring
-purine: A G
-pyrimidine: U T C

Question 4

structure of DNA

Answer 4

-double stranded
-ATCG
-asymmetrically aligned causing major and minor grooves which allow factors to interact with the bases
-46 chromosomes
-DNA packed into chromatin then into chromosomes
-DNA wraps around nucleosome
-centromere= constricted region of chromosome that’s involved in the segregation of chromosomes
-end of each chromosome has a telomere (noncoding region that protects structure)
-telomere shortens with each successive replication to prevent more replication
-nucleosome regulates gene expression by determining if DNA can be accessed by transcription factors
-modification of amino group of histone changes shape and electrical charge to prepare chromatin for DNA rep/transcip.

Question 5

what are nucleosomes and what do they regulate

Answer 5

histones, regulate gene expression by determining if DNA can be accessed by transcription factors

Question 6

what is a telomere and what happens to it when replication occurs

Answer 6

non coding region that protects the structure, shortens with each successive replication to prevent more replication

Question 7

what is a centromere

Question 8

what does enzymatic modification of amino terminal of histones do

Question 9

describe the structure of RNA

Answer 9

-AUGC
-3’ to 5’
-phosphodiester bonds, single stranded
-forms secondary and tertiary structures by folding and pairing with itself

Question 10

name the types of RNA

Answer 10

mRNA
tRNA
rRNA

Question 11

what is mRNA

Answer 11

carries genetic information from DNA to cytoplasm for translation

Question 12

what is tRNA

Answer 12

carries amino acids to ribosome to make proteins, cloverleaf shape

Question 13

name other uses of nucleotides

Answer 13

-energy
-intracellular communication

Question 14

differences between DNA and RNA

Answer 14

DNA- double stranded, ATCG, deoxyribose
RNA- single stranded, AUCG, ribose, can catalyse reactions, different types

Question 15

DNA replication how

Question 16

what are structural genes

Answer 16

proteins that encode for proteins

Question 17

what enzyme is used to transform DNA into RNA

Answer 17

DNA dependent RNA polymerase
pol i transcribes rRNA
pol ii transcribes tRNA

Question 18

describe a genes structure

Answer 18

5’–[]–//-[]-[]———-3’
-other regulatory sequences, promoters, coding regions
promoter sequence initiates transcription, factors bind and release RNA polymerase which needs to be phosphorylated to be activated

Question 19

what are promoter regions

Answer 19

specific sequence in DNA that determines where RNA polymerase binds

Question 20

how is RNA polymerase activated

Answer 20

phosphorylated

Question 21

DNA transcription summary

Answer 21

-RNA from DNA using RNA polymerase
-DNA copied in 3’ to 5’ so the RNA synthesised is 5’ to 3’
-RNA polymerase doesnt need primer to start (DNA poly needs it)
-initiation needs several protein factors to allow efficient RNA polymerase binding to promoter

Question 22

describe eukaryotic genes

Answer 22

-theyre modified to remove introns
(splicing) before mRNA is made
-contains exons and introns
exons= coding regions of protein
introns= non-coding regions