Cell Life Crisis
A cell can't make proteins. What organelle is likely malfunctioning?
What are ribosomes?
If a plant can no longer take in carbon dioxide, which process would be directly affected?
Photosynthesis would stop because CO₂ is a reactant.
Are viruses considered living or non-living?
What is non-living?
A mom has brown eyes (Bb) and a dad has blue eyes (bb). What’s the chance their child will have blue eyes?
50% chance. Punnett square shows Bb and bb.
DNA replication starts with this enzyme unwinding the double helix.
Helicase
A cell has a cell wall, chloroplasts, and a large vacuole. What kind of cell is it, and what do these structures do?
It’s a plant cell. Cell wall = structure, chloroplasts = photosynthesis, vacuole = storage.
A cell in saltwater begins to shrink. Explain why using osmosis terms.
Water leaves the cell (hypertonic solution), causing it to shrink.
A student gets a vaccine for chickenpox. A month later, they're exposed but don’t get sick. What happened inside their body?
The vaccine trained their immune system to recognize the virus and make antibodies before it could spread.
In guinea pigs, black fur (B) is dominant over white (b). Two guinea pigs with Bb are crossed. What are the genotype and phenotype ratios?
Genotype: 1 BB : 2 Bb : 1 bb; Phenotype: 3 black : 1 white
Transcribe this DNA sequence: TAC GGA CCT.
mRNA: AUG CCU GGA
A mutation causes lysosomes to stop working. Predict what happens inside the cell.
Cell builds up waste it can’t break down, possibly harming itself.
A student says, “Water moves into the cell during diffusion.” Correct them using science vocabulary.
That’s osmosis, not diffusion — osmosis is water moving through a membrane.
You have a bacterial infection. Your doctor says antibiotics will help. Why won’t those same antibiotics work if you had the flu?
Flu is caused by a virus, and antibiotics only kill bacteria.
Explain how a child can have a recessive trait even if neither parent shows it.
If both parents are carriers (heterozygous), they can each pass on the recessive allele, resulting in the child being homozygous recessive.
Translation takes place in the ______ and produces ______.
Ribosome; proteins
You find a simple cell with no nucleus but a membrane and ribosomes. Is it prokaryotic or eukaryotic? Explain.
Prokaryotic—it lacks a nucleus but has the basics like ribosomes and a membrane.
A red blood cell is placed in pure water. Predict what will happen and explain why.
Water will rush into the cell (hypotonic), causing it to swell and possibly burst due to osmosis.
A virus infects a host cell and uses it to build new viruses. Which stage of the lytic cycle is this, and what’s the result?
That’s the replication and assembly stages. The result is the host cell bursting open, releasing new viruses.
You cross a homozygous dominant tall plant (TT) with a short plant (tt). What will all the offspring look like and why?
All will be tall because they are heterozygous (Tt) and tall is dominant.
During DNA replication, one strand is built continuously and the other in fragments. Explain why this happens and name the fragments formed.
DNA polymerase can only add nucleotides in the 5' to 3' direction, so the leading strand is built smoothly toward the replication fork, while the lagging strand is built in short fragments (called Okazaki fragments) away from the fork.
Compare mitochondria and chloroplasts by function and which cells they're found in.
Mitochondria = ATP production in all eukaryotes; chloroplasts = photosynthesis in plants only.
Why do plant cells need both chloroplasts and mitochondria?
Chloroplasts make glucose; mitochondria turn it into ATP.
You look at a bacteria under a microscope. It's spiral-shaped and appears in clusters. How would you name it using shape and arrangement?
Spirillum (shape), staphylo (cluster) → Staphylospirillum (theoretically).
Two parents are both carriers for cystic fibrosis (Cc). Use a Punnett square to explain the chances of a child having the disease.
25% chance (cc), because only one combination gives two recessive alleles
A mutation changes an mRNA codon from UAU (tyrosine) to UAA. Use a codon chart to explain the result.
UAA is a stop codon, so the protein would stop being built early and could be nonfunctional.