Genetics

the science of heredity (observable traits and how they're passed through generations)

Molecular Biology

the science dealing with DNA and protein synthesis

What is a genome?

the total DNA in a cell

What does a genome consist of?

chromosomes and plasmids

What do chromosomes carry?

genes

what is a gene?

a section of DNA that codes for a functional product

DNA is a ___1___ made of _____2____

1. Macromolecule

2. Nucleotides

What 3 parts make up a nucleotide?

a nitrogen base

a 5 carbon sugar

a phosphate

What are the 4 possible bases of a DNA nucleotide?

Adenine

Guanine

Cytosine

Thymine

 What are the 2 differences between a DNA nucleotide and an RNA nucleotide?

In RNA, Thymine is replaced by Uracil and the sugar is ribose

How are the strands in a double helix held together?

Hydrogen bonds between specific bases

A bonds with ___1___

G bonds with ___2___

This is called ___3___

1. T

2. C

3. Base pairing

"Strands of DNA are complimentary to one another"

What does this mean?

The sequence of one determines the sequence of another

How are nucleotides linked to one another?

by covalent phosphodiester bonds

Where is the covalent phosphodiester bond that links nucleotides together located?

Off the phosphate

Does DNA replicate before or after division?

before

DNA is used to make ___1___ inside cells

proteins

What is recombination?

DNA flowing between 2 different bacterial cells

How does the fact that DNA strands are complimentary aid in it's replication?

One strand can be used as a template for synthesis of the other

What are the 3 steps of DNA Replication?

1. A small segment of double stranded DNA unwinds and the strands are separated.

2. A short RNA primer is produced.

3. DNA synthesis by an enzyme

What is a replication fork?

the part of DNA that unwinds and separates

What is responsible for unwinding and separating DNA strands during replication?

Which is ONLY found in bacteria?

Enzymes: DNA gyrase and helicase

DNA gyrase

What helps produce a small RNA primer?

Enzyme: Primase

What does the short RNA primer do?

It's an attachment site for nucleotids form a new strand of DNA

What does DNA pilimerase do?

links nucleotides together through phosphodiester bonds

What type of bond joins the parent strand and the new strand together?

Hydrogen bonds

What is the leading strand?

The first strand which is continous in the 5' to 3' direction

What is the lagging strand?

The second strand which is discontinous

What are Okazaki fragments?

What joins them together?

Small fragments of DNA

Enzyme: DNA ligase

What is transcription?

Synthesis of a complimentary RNA strand from a DNA template

What does messenger RNA do?

Carries coded information for making specific proteins

What does ribosomal RNA do?

forms part of the ribosomes - site of protein synthesis

What does transfer RNA do?

Carries specific amino acids to the ribosomes - used to make proteins

What 3 things does transcription require?

1.Supply of RNA nucleotides

2. A DNA template

3. Enzyme: RNA polymase

What are the 5 steps in Transcription?

1. RNA polymase binds to DNA at specific site – the promoter

2. RNA polymase assembles nucleotides into a new RNA chain
3. RNA polymase moves along the chain
4. RNA polymase reaches the end of the cahin - the terminator
5. RNA polymase and the new RNA strand are released

What are the 6 steps of translation?

1. mRNA attaches to the ribosome

2. tRNA carrying the correct amino acids enters the ribosome

(repeated) 3. Then binds to mRNA

(repeated) 4. Two amino acids are joined by peptide bond

5. Ribosome moves down mRNA in 5' to 3' direction

 6.mRNA and protein are released from ribosome

What is a mutation?

a change in the nucleotide sequence of DNA which can cause a change in the protein encoded by a gene

What are the 3 types of mutations?

1. Point mutation

2. Missense mutation

3. Frameshaft mutation

 What is a point mutation?

a single nucleiotide is replaced by another nucleotide

What is a missense mutation?

when a single amino acid has been changed