Biology MUST MEMORISE

Define amphipathic

Name a compound that is amphipathic

A chemical compound containing both a polar region and non-polar region

Phospholipids

Approach for detection related questions (fluorescence)

• Fluorescent label attached to…

• …detected by the…due to the fluorescence they emit

…tissues grow under strict regulation

• Halting the cell cycle when cell has not completed previous phase properly

• Cells with damaged DNA not allowed to divide so that DNA repair can take place

• Check for DNA replication, DNA damage, and chromosome-to-spindle attachments

• Prevent accumulation of mutations in daughter cells

If qns says that an organism heterozgous for a certain gene is advantageous what is this?

Heterozygote adavantage

Distinguish between repressible and inducible operons

• Repressible operons’ default operon expression is on while inducible operons’ default operon expression is off

• Repressible operon occurs in an anabolic pathway whereas inducible operon occurs in a catabolic pathway

• In repressible operon, repressor only binds to operator after a corepressor is bound to it but in inducible operon, the repressor binds directly to the operator

What to note about tyrosine kinase receptors?

Phosphorylation/Cross-phosphorylation of tyrosine residues in the intracellular domain of the receptor!!!

Why phosphorylation of STAT allows for its dimerisation?

Phosphorylation of STAT changes its conformation, so that it is complementary in shape and charge to another phosphorylated STAT

What to note when qns ask how something inhibits something else?

State the type of inhibition

The type of enzymes that inactivate the receptor

Phosphatase

What to note when explaining why a syndrome is a specific inheritance (e.g. autosomal dominant)

• Genetic disorder rare/not rare → unlikely/likely to be carrying allele

• Offspring inherited a…allele from one parent and a…from another parent

• Heterozygotes affected?

• Affected father produced an unaffected daughter or not?

Qns on supporting natural selection/Descent with modification, how a particular trait has evolved

• Variation in phenotype in the population

• Selection pressure on phenotype

• Selective advantage

• Able to survive and reproduce and pass down advantageous allele to next generation

• Increase in allele frequency in gene pool

Questions on how different species formed/speciation process

• Each population selected by different selection pressures → change in allele frequency

• Identify the type of reproductive isolation (geographical, behavioural, physiological)

• Gene flow impeded

• Each population’s gene pool accumulates mutations independently

• Over time, fertile members of two population unable to interbreed to produce viable and fertile offspring

• Identify the type of speciation (sympatric/allopatric)

Define adaptive radiation

An evolutionary process where a single ancestral species rapidly diversifies into many new forms to fill different ecological niches

Anatomical vs Homologous vs Analogous vs Vestigial structures

Anatomical: Pertaining to the body structure of an organism

Homologous structures: Similar internal anatomy and common ancestry

Analogous structures: Same job or function in different species but have different underlying anatomies and evolved independently

Vestigial structures: Reduced or non-functional remnants of body parts

Why a protein would be a good choice for study

• (Structural protein, if it actually is), very stable, less likelihood of degradation

• Common to animals

• Large amounts hence sufficient amounts