UNIT 4 - Molecular biology

What do non living organsims use?

RNA

What are the 4 type of biological molecules?

Carbohydrate

Lipid

Proteins

Nucleic acid

What is the function of nucleic acid?

Passes information through generations due to DNA replication

Protein production nitrogenous bases code for protein in gene expression

What is DNA?

deoxyriobsenulceic acid code for RNA in transcription

What is RNA?

RIbosenucleicacid codes for making protein in translation (protein synthesis)

What are nucleotides?

The sub units of DNA and RNA

What is the structure of a nucleotide?

Nitrogenous base, a 5 carbon sugar and one to three phosphate groups,

One universal factor of living organisms is?

What is a nucleotide?

A monomer unit of nucleic acids

What is the backbone of DNA?

Covalent bond between deoxyribose and phosphate molecules

What is complementary base pairing?

Base pairs of A-T and G-C bond together by hydrogen bonds and are equal lengths

How is complementary base pairing important in the replication of DNA as genetic material?

• When two strands of DNA are separated each strand is used as a template to build new strands

• Ensures base pairing is correct so new stands of DNA have the same sequence as the original

How is RNA formed?

Through condensation reactions in a single strand of nucleotides

The two strands of DNA are?

• Antiparallel

• Linked by hydrogen bonding

Compare DNA and RNA?

• The pentose is ribose in RNA and deoxyribose in DNA

• DNA has the base thymine but RNA has the base uracil instead

• RNA has one strand of nucleotides while DNA has two

What are the 3 roles of base pairing?

• DNA replication

• Transcription

• Translation

What is DNA replication?

Sequences of bases in DNA copied accuratley

What is transcription?

The process of making RNA from DNA

What is translation?

the decoding of an mRNA message into a protein

What is the role of helicase?

Unwinding the double helix and breaking the hydrogen bonds

What is the role of polymerase?

Links nucleotides together to form new strands using pre-existing strand templates

Which way do DNA polymerase?

The move in opposite directions

What is the repilication fork?

The site where a parent DNA molecule is seperated into two single strands

In multicellular organisms what is the 3 part process of cell divison?

• Growth

• Replacement of damaged tissue

• Reproduction to provide cells that develop into gametes

What is semi conservative replication?

Each of the DNA molecules produced has one new strand and one strand conserved from the parent molecule

What is polymerase chain reaction(PCR)?

A technique used for copying DNA artifically this happens in small tanks called eppendorfs

What do eppendorfs contain?

• DNA sample

• TAQ DNA polymore(heat stable)

• DNA nucleotides for assembling new strands

What are the stages of PCR?

• Denaturation (to seperate the two strands)

• Annealing (temp reduced to allow primers to bind to both strands of DNA)

• Elongation (temp increased to encourage tad polymers to replicate both strands)

What is gel electrophoresis?

a laboratory method used to separate mixtures of DNA, RNA, or proteins according to molecular size

What is the role of enzymes in DNA replication.

• Helicase breaks the hydrogen bonds (between base pairs) and unwinds the double helix

• DNA polymerase adds complimentary base pairs by adding nucleotides to the growing DNA strand

How do cells control the protein manufactured by the cell

By controlling transcription

What does the genetic code do?

Allow translation to form a polypeptide

What is triplet code?

A codon consisting of 3 base codons for one amino acids

What is degeneracy code?

When there are more codons than the minimum needed for the 20 amino acids

What is universality code?

The 64 codons of the genetic code have the same meanings in the cells of all organisms apart from a few variations

How can a protein structure be changed by a mutation?

A bases substitution can change one codon in mRNA transcribed from the gene

What base substitutions have no effect?

• Base substitutions with the same sense mutation

• Base substitutions that are chemically similar to the original

What is the elongation?

The formation of the polypeptide chain

How does a polypeptide chain elongate as the ribosome moves along an mRNA molecule?

• tRNA molecules attach to corresponding amino acids

• tRNA anticodons bind to the mRNA codon binding

• The amino acid forms a peptide bond with the previous amino acid in the polypeptide chain

• The ribosome moves down the mRNA molecule

• The polypeptide elongates one amino acid at a time

What are the roles of RNA in translation

• mRNA messenger rna

• tRNA transfer rna

• rRNA ribosomal rna