3/22/24 - DNA exam

3 parts of a nucleotide

• a nitrogenous base

• a pentose sugar

• a phosphate

4 nitrogenous bases

Adenine - Thymine

Guanine - Cytosine

Name and role of DNA

• Deoxyribonucleic acid

• contains the instructions needed for an organism to develop, survive and reproduce

Name DNA polymerase

• α, β, γ, δ, and ε. Polymerase

• γ is located in mitochondria

Role of DNA polymerase

• to accurately and efficiently replicate the genome in order to ensure the maintenance of the genetic information and its faithful transmission through generations.

Name of DNA helicase

Polarity

Role of DNA helicase

a catalyze the disruption of the hydrogen bonds that hold the two strands of double-stranded DNA together.

steps of replication

• the opening of the double helix

• separation of the DNA strands

• priming of the template strand

• the assembly of the new DNA segment

RNA vs DNA

RNA

• Ribose sugar

• Single strand

• Uracil

• DNA

• Deoxyribose sugar

• Double strand

• Thymine

• BOTH

• Nucleic acid

• Adenine

• Guanine

• Cytosine

• Phosphate

steps of transcription (know/understand bolded steps!)

SIMPLE

• Genes —> RNA —> Amino acids —> proteins —> Traits

• Needs to copy the gene into RNA than RNA codes for remaining proteins

  NOT SIMPLE

• Copy DNA into messenger RNA

• Copied from the coding strand

• DNA turns to complimentary mRNA

• The enzyme RNA polymerase makes

  —<>—

• Before mRNA is ready for use it needs to be “cleaned” or “edited”

Product of transcription

RNA, mRNA, tRMA, rRND

What does genetic code refer to

The codons code for a specific amino acid

Step 2 - Translation

• RNA leaves nucleus

• Ribosome attaches to mRNA

• Ribosome gathers right amino acids

• Amino acid attaches to growing chain

• Product = Protein

Product of translation

Protein

Step 3 - Protein → Trait

Many proteins are enzymes that determine which chemical reactions take place in a cell-color production, size, movement, hormone production…

What nucleotide letter changes from DNA to RNA?

A → U

Where does transcription happen?

The nucleus

Where does translation happen?

On ribosomes in cytoplasm

Whats polymerase

A group of enzymes that catalyse the synthesis of DNA during replication

Three types of mutation

Point mutation - Insertion/Deletion - Chromosomal mutation - Significance of mutation

Point mutation

• One base is changed to another

• Usually affects a single amino acid

• Can have no effect - be beneficial - or be harmful

Insertion/Deletion

• Much more serious

• Causes a frame shift

• Changes every amino acid that follows the mutation

Define frame shift

All amino acids in the frame move down one

Chromosomal mutation

• Mistake in the structure of the chromosomes

• Can include deletions - duplication - insertions - translocations

Significance of mutation

• Most are neutral

• Some are harmful

• Genetic disorders (gametes)

• Cancers (gametes or somatic)

• Some are beneficial

• Natural selection

• Artificial selection by farmers and breeders