Unit 1: Chemistry of Life
What is the difference between a saturated and unsaturated lipid.
Saturated = no double bonds ; unsaturated = at least one double bond
This ratio limits cell size. What happens when this ratio decreases?
SA:V ratio. When it decreases, the cell becomes less efficient at exchanging materials (nutrients, waste, gases), which limits growth and can trigger division.
List two environmental factors that could cause an enzyme to denature.
temperature; pH
What is a ligand?
A chemical signal that binds to a receptor to activate a response
What is a genotype vs. phenotype?
Genotype = allele combination; phenotype = observable traits.
List three properties of water.
Acceptable answers: polarity, expansion upon freezing, high specific heat, cohesion/adhesion, capillary action, high surface tension
Eukaryotic DNA is ______, while prokaryotic DNA is ______.
Linear, circular
Describe what happens during allosteric inhibition.
An inhibitor binds to a regulatory (non-active) site, causing a shape change that decreases the enzyme’s ability to bind substrate.
What happens in S phase?
DNA replicates → forms sister chromatids attached at a centromere.
What does meiosis produce?
Four genetically unique haploid gametes.
Explain hydrolysis and dehydration synthesis
Hydrolysis: cleaving of covalent bonds with the addition of water. ; dehydration synth: removes water to join two monomers. (polymerization)
Rough ER focuses on _____ synthesis, while smooth ER focuses on _____ synthesis and _____ cells.
Protein; lipids; detoxifying/detox of
Where does the Calvin Cycle occur?
In the stroma of the chloroplast.
What is a G-protein-coupled receptor (GPCR)?
A membrane-bound receptor that spans the membrane seven times and, upon ligand binding, undergoes a conformational change that activates an associated G-protein by promoting GDP–GTP exchange, triggering an intracellular signaling pathway.
What happens in Prophase I?
Homologs pair (synapsis), crossing over may occur, chromosomes condense, spindle forms, nuclear envelope breaks down.
What are three components of a nucleic acid? (+100 if you can list the base pairings in DNA and RNA).
Five-carbon sugar, phosphate, nitrogenous base
Bonus: A->T, A->U (RNA), C->G
List 4 things all cells have in common.
Ribosomes, Cytoplasm/Cytosol, genetic material (DNA/RNA), plasma membrane
List two products of glycolysis.
2 pyruvate; 2 ATP (net) or 2 NADH.
Predict what happens if a cell lacks a receptor for a hormone.
It will not respond, even if the hormone is present (no reception = no pathway).
Name Mendel’s two laws and what they state.
Mendel’s Law of Independent Assortment: Alleles separate so each gamete receives only one allele per gene.
Mendel’s Law of Segregation: Genes on different chromosomes assort independently during meiosis.
Come up to the board and draw the structure of an amino acid and label all the components.
Carboxyl group, amine group, central carbon, r group, lone H
Give two pieces of evidence for the endosymbiotic theory.
Mitochondria and chloroplasts are self-sustaining, have their own ribosomes, double-membraned.
What does decoupling in the electron transport chain generate?
Heat, because proton flow is released without producing ATP.
Walk through mitosis from prophase to cytokinesis.
Prophase = chromosomes condense, spindle forms.
Metaphase = chromosomes line up.
Anaphase = sister chromatids separate.
Telophase = nuclear envelopes reform.
Cytokinesis = cell splits.
What is a testcross, and what is it used for?
Cross with a homozygous recessive to determine an unknown genotype.