Cellular Respiration
What is the overall purpose of cellular respiration in cells?
To convert chemical energy in glucose into usable cellular energy (ATP).
What 3 main things does photosynthesis convert (starting material -> product)?
Converts light energy + CO2+ H2O into chemical energy (glucose) and oxygen.
State the Central Dogma of molecular biology in the simplest form
DNA → RNA → Protein
What is the main purpose of mitosis in multicellular organisms?
To produce genetically identical daughter cells for growth, repair, and asexual reproduction.
What is the difference between a genotype and a phenotype?
Genotype = genetic makeup (alleles)
Phenotype = observable traits
Give the balanced chemical equation for cellular respiration (symbols and words)
C6H12O6+6O2→6CO2+6H2O+energy (ATP)
glucose + oxygen → carbon dioxide + water + ATP.
Where in the cell does photosynthesis happen, and what organelle is responsible?
In chloroplasts of plant cells
Name the three main types of RNA and give one function for each (mRNA, tRNA, rRNA).
mRNA (carries coded instructions from DNA)
tRNA (brings specific amino acids)
rRNA (structural and catalytic part of ribosome)
List the phases of mitosis in order (use PMAT) and give one visible feature of each phase under a microscope.
Prophase (chromosomes condense, nuclear envelope breaks down), Metaphase (chromosomes align at metaphase plate), Anaphase (sister chromatids separate), Telophase (chromosomes decondense, nuclear envelopes reform).
Define homologous chromosomes vs. sister chromatids.
Homologous chromosomes: same genes, one from each parent
Sister chromatids: identical copies from DNA replication, joined at centromere
Name the 4 main stages of aerobic cellular respiration and state where each occurs in the cell.
1. Glycolysis (cytoplasm)
2. Link reaction / pyruvate oxidation (mitochondrial matrix)
3. Citric acid/Krebs cycle (mitochondrial matrix),
4. Electron transport chain (inner mitochondrial membrane).
Write the overall photosynthesis equation in symbols and in words.
6CO2+6H2O+light energy→C6H12O6+6O2
carbon dioxide + water + light → glucose + oxygen.
What are the two main steps of protein synthesis? For transcription, name the enzyme that synthesizes RNA and the base-pairing rule used when making mRNA from DNA.
Transcription (DNA → mRNA by RNA polymerase; base pairing A→U, C→G), then processing (splicing, cap, tail). Translation (mRNA → polypeptide at ribosome).
What is a telomere and how is it related to repeated cell divisions (why described as a “molecular clock”)?
Telomeres are repetitive DNA at chromosome ends that shorten with each division; when too short, cells stop dividing (senescence), so length tracks division history.
Explain nondisjunction and give one example disorder that results from it.
Nondisjunction = failure of chromosomes to separate; can cause trisomy (e.g., Down syndrome, trisomy 21) or monosomy (e.g., Turner syndrome, monosomy X).
During glycolysis, what is the net yield of ATP and NADH per glucose molecule? What is the primary goal of glycolysis?
Net yield glycolysis: 2 ATP (net) and 2 NADH per glucose.
Goal: split glucose into pyruvate and capture some electrons (NADH)
Distinguish where the light reactions and the Calvin cycle occur inside the chloroplast, and name one major product of each.
Light reactions occur in the thylakoid membranes (make ATP and NADPH, release O2). Calvin cycle occurs in the stroma (uses ATP + NADPH to fix CO2 into sugar).
During translation, what are the three ribosomal sites (letters) and what is the order of tRNA movement through them?
A (arrival) site, P (protein) site, E (exit) site.
Order: tRNA enters at A, moves to P as peptide bond forms, then to E to exit.
Define metastasis and angiogenesis as they relate to cancer progression.
Metastasis: spread of cancer cells to new body sites. Angiogenesis: growth of new blood vessels to supply a tumor.
Explain how incomplete dominance differs from codominance, with a short example for each.
Incomplete dominance: heterozygote shows intermediate phenotype (red + white → pink). Codominance: both alleles expressed equally (blood type AB, or roan cattle).
Describe the electron transport chain’s role in producing ATP. Include the role of the proton gradient and oxidative phosphorylation; state an approximate total ATP yield per glucose (typical textbook value).
ETC uses electrons from NADH/FADH2 to pump protons across the inner membrane, creating a gradient; ATP synthase uses the proton flow to make ATP (oxidative phosphorylation).
Typical total yield ≈ 30–36 ATP per glucose (textbook values vary).
Explain how light wavelength (color) and light intensity affect photosynthesis and why.
Blue and red wavelengths are most effective because chlorophyll absorbs them best; higher light intensity increases rate up to a point until other factors limit photosynthesis (like CO2 or temperature).
Define a frameshift mutation and explain why it tends to be more damaging than a silent point mutation.
Frameshift: insertion or deletion that shifts the reading frame, changing all downstream codons — usually produces nonfunctional protein. Silent point mutation changes a codon without changing amino acid — least damaging.
Compare proto-oncogenes and tumor suppressor genes (like p53). Explain what happens when each type mutates and how that contributes to cancer.
Proto-oncogenes promote cell division; mutation can create oncogenes that cause excessive division (gain of function).
Tumor suppressors (e.g., p53) normally inhibit division or promote repair/apoptosis; loss-of-function mutations remove these brakes, allowing uncontrolled growth
Briefly describe how crossing over and independent assortment during meiosis increase genetic variation.
Crossing over (prophase I) exchanges segments between homologs; independent assortment (metaphase I) randomly sorts maternal/paternal homologs — both increase genetic combinations in gametes.