Unit 1
A DNA strand mutates from UGG → UGA. What type of mutation is this most likely, and how might it affect the protein?
Nonsense mutation, it will cause the protein to be too short and not function properly
A cell is placed in a hypertonic solution. What happens to the cell?
Water leaves the cell and cell shrinks.
Why is cellular respiration considered exergonic?
It releases energy
A heterozygous tall pea plant (Tt) is crossed with a short plant (tt). What % of offspring are tall?
50%
If a population is in Hardy-Weinberg equilibrium, what is true?
No evolution is occurring.
If DNA replication occurs but DNA polymerase fails to proofread, what is the most likely outcome?
More chance of mutations
Which organelles would be most active in a cell producing large amounts of protein for export?
Rough ER and Golgi apparatus.
What happens to ATP production if oxygen is unavailable?
Switch to anaerobic respiration and less ATP produced.
Why does meiosis increase genetic variation?
Crossing over and independent assortment
What is the main difference between r-selected and K-selected species?
r-selected = many offspring, low care; K-selected = few offspring, high care.
A DNA template strand reads TAC GGC ATT. What mRNA sequence is produced after transcription?
AUG CCG UAA
If a cell has damaged mitochondria, what process is most affected?
ATP production (cellular respiration).
Which stage of cellular respiration produces the most ATP?
Oxidative phosphorylation
If nondisjunction occurs in meiosis, what can result?
Extra or missing chromosomes
A small population becomes genetically different just by chance after a disaster. What is this called?
Genetic drift (bottleneck effect)
A cell has a mutation that prevents tRNA from binding to codons. What process is directly disrupted?
Translation (protein synthesis stops)
Which macromolecule would most likely be used for long-term energy storage and insulation?
Lipids
Where in the cell does glycolysis occur, and why is this important?
Cytoplasm; it does not require oxygen or mitochondria
A mutation occurs in a somatic cell. Is it inherited? Why or why not?
No, it is not passed to offspring.
In 2024 the allele frequency was .80 A and .20 a but in 2026 the allele frequency was .81 and .19
Did evolution occur
Yes
During replication, one DNA strand is copied continuously while the other is copied in fragments. What are these fragments called?
Okazaki fragments
Why does a protein lose function if its shape changes?
Function depends on 3D shape (denaturation changes active site)
Why does aerobic respiration produce significantly more ATP than anaerobic respiration?
Oxygen allows the electron transport chain to run, producing much more ATP via oxidative phosphorylation
Why does crossing over increase genetic variation?
It exchanges DNA between homologous chromosomes, creating new allele combinations
A population of rabbits becomes darker over time due to predators. What type of selection is this?
Natural selection (directional selection).