DNA Flashcards
Role of DNA in protein synthesis
contains code for amino acids
Function of genes
determine characteristics
Chromosomes are made of…
protein and DNA
DNA stands for
deoxyribonucleic acid
smallest part of DNA
nucleotide
Structure of nucleotide
Phosphate—–Sugar—–Base
Structure of nucleotide in DNA
Phosphate—–Deoxyribose—–Adenine, Guanine, Thymine or Cytosine
Purine DNA bases
Adenine, Guanine
Pyrimidine DNA bases
Thymine, Cytosine
Many nucleotides joined together
Polynucleotide chain
Structure of DNA
two polynucleotide chains twisted together in DNA double helix
Base pairs in DNA
A=T, C=G
A and T are joined by
two hydrogen bonds
G and C are joined by
three hydrogen bonds
DNA replication occurs when?
During interphase of mitosis
DNA replication steps
1: DNA double helix uncoils
2: Enzymes break the bonds between base pairs
3: Replicated according to template of old DNA strand
4: 2 identical DNA molecules twist, double helixes formed
RNA stands for
ribonucleic acid
Differences between RNA and DNA
RNA…………………DNA
ribose………………deoxyribose
single stranded..double stranded
A,G,U,C…………….A,G,T,C
can enter…………nucleus only
nucleus/move
around in cytoplasm
What determines sequence of bases on RNA?
RNA builds itself up according to template on DNA
Protein synthesis
how genes make proteins Eg: Keratin, enzymes, hormones
RNA types involved in protein synthesis
messenger RNA, transfer RNA, ribosomal RNA
Step names for protein synthesis
enzyme unwinds DNA 2x helix in gene, Transcription, Translation
Transcription definition
rewriting of DNA code to strand of mRNA
Translation definition
production of protein according to code on mRNA
Where does translation occur
mRNA goes to ribosome
Translation steps (5)
1.Codons (3 bases) on mRNA code for 1 amino acid
2.tRNAs pick up specific amino acid in cytoplasm + carry to ribosome
3.Anticodon on tRNAmatches codon on mRNA, brings acid into position
4.Amino acids joined together by peptide bonds, chain folds to become a protein
5.tRNAs continuously leave ribosome
Process by which double stranded molecules are formed from single stranded molecules
replication
Where in the cell does replication take place
nucleus
codons code for one of three possible outcomes during protein synthesis. Name the 3 outcomes
Start, addition of amino acid, stop
Molecule that carries complementary bases to mRNA molecule
tRNA
Definition of gene
Section of DNA that codes for protein
Opening through which mRNA leaves nucleus
nuclear pore
Ribosomes are composed mainly of
rRNA
Two non-nuclear locations of DNA in cells are…
mitochondrion or chloroplast
Name the group of chemicals to which the nitrogenous compounds in nucleic acids belong
Bases
Why does joining of amino acids eventually cease
stop codon reached
