Carroll Bio 2 - Midterm #2

Primary Protein Structure

Level of structure whose shape and function is determined by its amino acids and their order when bonded together into a polypeptide.

Secondary Protein Structure

Level of structure whose shape and function is determined by hydrogen bonds between amino acids in a polypeptide forming alpha-helixes and beta-sheets.

Tertiary Protein Structure

Level of structure whose shape and function is determined by disulphide bridges and hydrophobic interactions between amino acids in a polypeptide.

Quaternary Protein Structure

Level of structure whose shape and function is determined by multiple polypeptides connecting with ionic bonds to form larger complexes.

Transport Signal Sequence

Specific chain of amino acids found towards the end of a protein which denotes that protein for movement/removal.

Often found on disruptive or messenger proteins.

Often composed of lots of hydrophobic aminos.

Ex: insulin is tagged with a chain to allow it into intracellular signalling.

Proteolysis

Post translation modification where the protein is cleaved to change its shape or remove useless DNA.

Some prokaryotes translate 1 long protein with multiple genes and cut them up into proteins after.

Glycosylation

Post translational modification where carbohydrates are added to proteins as signals for coding and recognition.

Phosphorylation

Post translational modification where a phosphate group is added to a protein to cause some kind of change

Can cause the protein to become hydrophillic/phobic or activate/deactivate.

NSP1 Protein

Protein found in SARS-CoV-2 and many other viruses which binds to ribosomal small unit of the host cell to block any host mRNA from translation while allowing viral mRNA to be translated.

Horse Athleticism

Equines are hyper efficient runners, which is anaerobic exercise.

Anaerobic exercise burns oxygen and produces toxic reactive oxygen species.

Equines avoid problems with these toxins due to KEAP1 gene mutation from early equine ancestors allowing them to produce more antioxidants.

Mutation

Heritable change in a nucleotide sequence.

2 types: spontaneous & induced

Frequency: 1 / 3,000,000 base pairs each replication are affected.

NOT errors in transcription or translation.

Spontaneous Mutation

Naturally occuring mutation caused by replication errors and accidental reactions causing base changes.

Errors also appear during meiosis due to chromosomal mismatching and sister chromatids bunching together, leading to some haploid germ cells having 0 chromatids while others have 2.

Induced Mutation

Mutation caused by exposure to outside physical, chemical, or radioactive agents.

Happen more often than natural mutation.

Phenotype Mutation

Eukaryotes are often diploids so some base errors can be overshadowed by dominant chromosome expression.

Ex: Sickle cell anemia is caused by a single point error which causes loss of blood cell function in homozygotes, but also gives malaria resistance if heterozygotic.

Ex: P53 tumor suppressor gene can have single base change which causes it to promote cancer.

Errors in the redundant DNA do not often lead to problems.

Mutation in Heredity

DNA errors only matter for inheritance if they happen in germ cells.

To avoid this, germ cells have high error checking, reducing error by up to 10x.

Mutation in Fitness

Many errors are deleterious but can persist throughout generations.

Mutation rate, age at expression, heterozygote advantage (sickle cell), and polyploidy can contribute to this.

Point Mutations

Errors that change only a single base, effects may be larger.

2 types: substitution, insertion/deletion

Substitution Mutation

Error which involves the switching 1 base in a sequence of DNA.

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