Bacteria & Viruses
Name two differences between bacteria and viruses.
Bacteria can survive and reproduce on their own; viruses cannot. Bacteria are larger.
What is homeostasis?
Maintaining stable internal conditions despite external changes.
What process creates gametes with half the original chromosome number?
Meiosis
What is the correct order of information flow: DNA → ____ → protein?
RNA
Where does cholesterol naturally come from?
Animal products and the body’s own production.
Why don't antibiotics work on viruses?
Viruses lack structures (like cell walls or ribosomes) that antibiotics target.
Give one example of negative feedback in humans.
Sweating to cool down or shivering to warm up.
How does crossing over create new allele combinations?
Homologous chromosomes exchange DNA fragments.
Why do three-nucleotide insertions change proteins differently than single-nucleotide insertions?
Three nucleotides add one amino acid; one nucleotide shifts the entire reading frame.
Fat is in both avocados and bacon. Why does bacon contain cholesterol but avocados don’t?
Only animal products contain cholesterol.
Explain why an antibiotic might not kill every bacterium in a population.
Some bacteria may have traits (porins, pumps, protective layers) that reduce antibiotic effectiveness.
What type of feedback loop occurs when a woman is giving birth?
Positive Feedback
Why can siblings have different genetic combinations even with the same parents?
Independent assortment and crossing over produce unique gametes.
How can a protein differ even if the DNA is “almost” the same?
A small DNA mutation can change an amino acid.
Name two useful functions of cholesterol in the body.
Building cell membranes, making hormones.
Why are human cells not harmed by antibiotics that break down cell walls?
Human cells have no cell wall.
Why can maintaining high immune cell levels for too long be harmful?
It can lead to unnecessary inflammation or tissue damage.
Why might two genes located close together on a chromosome still end up inherited separately?
Crossing over can separate them.
Why do two cell types with the same DNA produce different proteins?
Different genes are expressed (turned on/off).
Explain why high cholesterol in the blood can be harmful.
It can build up in arteries and restrict blood flow to the heart.
A student notices some bacteria survive even after two different antibiotics are used. Explain the most likely reason.
Antibiotics work probabilistically — some bacteria naturally survive and can reproduce.
WILD: A DNA sequence is ATG–TTC–CGA–TCG–TGA. What is the significance of TGA?
It is a STOP codon.
A genetic model predicted genes PCSK9 and COL11A1 would always be inherited together, but a child inherited a new combo. Explain why.
Crossing over produced a new allele combination not predicted by the model.
n a DNA sequence, what happens during translation?
mRNA codons are read to build a chain of amino acids (protein).
List two risk factors for coronary artery disease.
Family history, high saturated fat intake, smoking, lack of exercise.