Cell Biology
Which organelle has two membranes - an inner and an outer?
The mitochondria
What are chromosomes?
Packaging units for organizing DNA
What is the term for when cancer spreads to a different/secondary site?
Metastasis
How does your brain sense what’s going on in the world?
The sensory nervous system
Name two key features of the cell/plasma membrane.
The cell/plasma membrane 1) is a phospholipid bilayer; 2) functions as a selectively permeable barrier (to keep molecules in/out)*
*Alternate answers: Consists of proteins, carbohydrates; connection for the cytoskeleton to the extracellular matrix; function – maintains overall cell structure (keeps cell in place)
Explain dominant and recessive traits, provide an example.
A dominant trait ‘overpowers’ a recessive one – these are represented as uppercase and lowercase letters, respectively
> Example: Brown is the dominant trait for eye colour (genotype, BB/Bb); therefore, to observe the recessive trait (blue/green), an individual must receive two copies of the recessive gene (genotype, bb)*
What cells are killed by chemotherapy?
Rapidly dividing cells
What’s the name of the nerve that transmits information from your eye to the brain?
The optic nerve
What is a stem cell and why are they important?
Special cells that can turn into other kinds of cells (differentiate). Stem cells are self-renewing, meaning they can make copies of themselves.
What is the gene ‘start’ site called?
Promoter
How does someone get cancer? List three possibilities.
Old age, occupational factors (exposure to harmful chemicals), genetics*
*Alternate answers: Lifestyle – smoking, diet (high consumption of processed foods, low intake of plant-based ingredients), substance abuse (high consumption of drugs, alcohol), low activity level (high body fat, obesity); environment – sunlight, contaminated water/food sources; infection – viruses
What neurotransmitter is used for inhibiting a postsynaptic neuron?
GABA
What percentage of DNA is shared between different cells in the same developed organism?
100%
Name, briefly describe a type of RNA.
Messenger RNA (mRNA) – encodes the amino acid sequence of a polypeptide (gene transcribed by RNA Pol II)
*Alternate Answers: Transfer RNA (tRNA) – brings amino acids to ribosomes during translation (gene transcribed by RNA Pol III); ribosomal RNA (rRNA) – makes up the ribosome in conjunction with other ribosomal proteins (gene transcribed by RNA Pol I, III); small nuclear RNA (snRNA) – forms a complex with proteins that are used in RNA processing by eukaryotes (gene transcribed by RNA Pol III)
Describe immunotherapy.
Immunotherapy is a modern approach to cancer treatment that is based on engineering our own cells to fight cancer cells
> Key features: 1) Personalized for each individual, cancer type; 2) Immune cells can recognize cancer cells by the expression of proteins that are unique to that cancer (detection/identification markers); 3) Strengthen immune cells by genetic engineering
Electrical signals propagate from a neuron’s dendrites to its axon terminal. What type of transmission typically allows communication across a synapse?
Chemical transmission
Name a mammalian cell that has no nucleus and one that contains many.
1) Red blood cell*; 2) Megakaryocyte**
**Alternate answers: Hepatocytes (liver cells), monocytes (immune cell – macrophage lineage), muscle fibers, osteoclasts (specialized bone cell) are all normal cells that often have multiple nuclei; in the case of disease, cancer cells and cells infected with viruses can also be multinucleated
What is the Law of Independent Assortment?
Genes for different traits are sorted separately from one another so that the inheritance of one trait is not dependent on the inheritance of another.
Every possible combination of alleles for every gene is equally likely to occur
Explain genome maintenance and the proofreading system, and why it is important.
DNA polymerase makes mistakes during replication. When incorrect bases are incorporated, the polymerase reverses directions, moving back one nucleotide. The wrong nucleotide is excised and replaced. If the proofreading system fails, this creates a hypermutated gene, which can lead to cancer.
Why are rods and cones located at the back of the retina even though they detect light?
There is no direct answer–this is just the solution that evolution converged to for allowing us to see