DNA & Genes
What molecule is the genetic material stored in cells and organized into chromosomes?
DNA
What is the name of the molecule made during transcription that uses U instead of T?
RNA (specifically messenger RNA, mRNA).
What is the name for a change in the base-pair sequence of a gene?
Mutation
When body cells divide, are mutations passed to the new cell? (Yes/No)
Yes
What term describes traits that help organisms survive and reproduce in their environment?
Adaptations
DNA has two strands made of repeating building blocks. What are these building blocks called?
Nucleotides
Which three-base sequences on a gene code for specific amino acids?
Triplets (codons).
List three ways base pairs can change when DNA is copied (three mutation types described).
Added, deleted, or substituted base pairs.
Which type of cells must contain a mutation for it to be inherited by offspring?
Reproductive cells (eggs and sperm).
Name one adaptation of the star-nosed mole described in the text and explain how it helps the mole.
Example: The star of sensory projections (22 finger-like projections) helps detect and capture prey quickly; specialized nervous processing aids rapid detection.
In sexually reproducing organisms, how many chromosomes does an offspring receive from each parent for each pair?
One chromosome from each parent.
How many different amino acids combine to make proteins (approximate number given)?
About 20 different amino acids.
Mutations may be beneficial, neutral, or harmful. Give one example outcome
A new skin color (or genetic disease, or no effect).
Sexual reproduction shuffles genes. Explain in one sentence how this leads to differences among offspring from the same parents.
Because shuffling (during Meiosis) produces new combinations of chromosomes, each gamete carries different gene combinations, so offspring differ.
The mountain goat has split hooves and strong rear legs. State whether these are structural, functional, or behavioral adaptations.
Structural adaptations (split hooves) and structural/functional (strong rear legs help climbing).
Which base pairs with adenine (A) in DNA?
Thymine (T).
Why does a protein’s shape matter for its function? Think why an Enzyme is shaped the way it is shaped.
Shape determines function; example: collagen folds into long fibers to strengthen skin, hormones fit target cells like a key in a lock.
If a mutation changes the sequence of amino acids in an enzyme, how might that affect the enzyme’s ability to bind its target?
The sequence of amino acids determines the shape of the enzyme, which determines the molecules it can bind
"Complete the DNA sequence by adding complementary bases." If one DNA strand reads A - G - T - CA - G - T - C, write the complementary strand.
Complementary strand: T - C - A - GT - C - A - G.
Describe one possible variation that might help mountain goats if climate change causes taller plants to cover rocks
Example variation: goats with longer legs or different grazing behavior that allow reaching taller plants, or thicker fur if microclimate changes
Define a gene in one sentence
A gene is a specific segment of DNA that provides instructions for an inherited trait.
Explain the base-letter change between DNA transcription and RNA translation (which letter is swapped and give the DNA/RNA base sets).
During transcription DNA's T is swapped for RNA's U; DNA uses A, T, G, CA, T, G, C while RNA uses A, U, G, CA, U, G, C.
Explain why some mutations can be passed from parent to offspring while others cannot. Use correct cell-type terms.
Mutations in reproductive cells (eggs or sperm) can be passed to offspring; mutations in body cells affect only the individual and are not inherited.
Over 25 million years a DNA sequence accumulated 4 mutations. Estimate how many mutations occur over 100 million years using proportional scaling and show your calculation.
Proportion: 4 mutations per 25 million years => scale factor 4 × (100/25) = 16 mutations per 100 million years.
Explain how genetic variation is necessary for natural selection to cause evolution. Use terms "mutation" and "sexual reproduction" in your answer.
Genetic variation from mutation and sexual reproduction produces different traits; natural selection acts on this variation so individuals with beneficial traits leave more offspring, changing the population over time.