Cell Types & Viruses
What is the smallest unit of life?
The cell
What biomolecule is the main source of energy for living things?
Carbohydrates
What organelle performs photosynthesis?
Chloroplast
What does DNA stand for?
Deoxyribonucleic acid
How many daughter cells are produced in meiosis?
Four
What type of cell lacks a nucleus—prokaryotic or eukaryotic?
Prokaryotic
What are the building blocks of proteins?
Amino acids
What gas do plants take in for photosynthesis?
Carbon dioxide (CO₂)
What are the complementary base pairs in DNA?
A–T and C–G
Are the cells made in meiosis identical or different?
Different
What structure controls what enters and leaves the cell?
The cell membrane
Which biomolecule stores genetic information?
Nucleic acids (DNA and RNA)
What are the products of cellular respiration?
Carbon dioxide, water, and ATP
During which phase of the cell cycle does DNA replicate?
S phase (synthesis)
What process allows cells with the same DNA to become different types of cells?
Cell differentiation
Are viruses considered living or nonliving? Explain why.
Nonliving – they can’t reproduce without a host cell
How do enzymes speed up chemical reactions?
By lowering the activation energy
How are photosynthesis and cellular respiration related?
The products of one are the reactants of the other
What enzyme unzips DNA during replication?
Helicase
What determines which genes are expressed in a cell?
Which genes are turned on or off
What is the main difference between a plant cell and an animal cell?
Plant cells have a cell wall and chloroplasts; animal cells do not
What two factors can cause an enzyme to denature (lose its shape)?
Extreme temperature or pH
In which organelle does cellular respiration take place?
Mitochondria
What happens during mitosis?
The nucleus divides, creating two identical nuclei
Why is meiosis important for sexual reproduction?
It produces gametes with half the number of chromosomes (haploid), ensuring genetic diversity