2.3 Nucleic Acids Flashcards
What does DNA stand for?
Deoxyribose nucleic acid
How many chromosomes are there in the human body?
23 pairs, 46 total
How many chromosomes do the egg and sperm have?
23
What are genes?
sections of DNA
What do genes do?
code for specific characteristics
What are genes that come in different forms called?
alleles
What are the nitrogenous bases?
Adenine - Thymine
Cytosine - Guanine
What are the parts of a nucleotide?
- Phosphate
- Pentose sugar
- Nitrogenous base
How many hydrogen bonds do A + T have?
2
How many hydrogen bonds do C + G have?
3
How do the base and sugar join?
Glycosidic bond
How do the phosphate and sugar join?
Phosphodiester bond
What sort of reaction do the bonds require?
Condensation reaction
What are the purines and what are their structure?
- Adenine + Guanine
- double ringed structure
What are the pyrimidines and what is their structure?
- Thymine + Cytosine
- Single ringed structure
What does semi-conservation mean?
one parent DNA strand and one new daughter strand
What does Gyrase do?
Unwinds DNA
What does Helicase do?
Unzips DNA
What does Primase do?
Signals where the nucleotides are added
What does DNA polymerase do?
adds the nucleotides
What does DNA ligase do?
sticks the lagging strand fragments
What are okazaki fragments?
short sequences of DNA nucleotides for lagging strands
What is the lagging strand?
the new strand of DNA whose direction is opposite to the direction of the old strand
When does DNA replication happen?
In the interphase before cell division
Why does DNA replication happen?
Because when cells divide, they need the same amount of DNA
What are the products of DNA replication?
2 semi conservative DNA strands
What does RNA stand for?
Ribonucleic acid
What are the 3 types of RNA?
- mRNA
- tRNA
- rRNA
In RNA, what does Adenine pair with?
Uracil
How do the sugar phosphate backbones run?
In opposite directions
What do hydrogen bonds between the bases do?
stabilise the structure
How do the bases pair?
Purine to pyrimidine
What do RNA molecules do?
Convert the instructions in DNA
What sort of sugar does RNA have?
ribose
What is a protein?
- Polymer of units linked by peptide bonds
- built up from 20 amino acids
What is transcription?
When DNA is read to produce a strand of mRNA
What does RNA polymerase do?
binds to DNA strand and unwinds small section to travel along building an RNA molecule from the template strand.
What is translation?
Where mRNA is read to produce a strand of protein chain
What is tRNA?
Short strand of RNA which carries anti codon
What does tRNA attach to?
mRNA strand
What do anticodon molecules have?
area with 3 bare bases which match to corresponding bases on mRNA
How can you describe the arrangement of the DNA molecule?
antiparallel
