Cell Cycle Basics
What are the three main parts of the cell cycle?
Interphase, mitosis, and cytokinesis.
What is mitosis (brief definition)?
process by which new cells are made for growth and repair
What is meiosis used to produce (what type of cells)?
Gametes (sperm and egg).
What are the four nitrogen bases in DNA? (list)
Adenine, Thymine, Guanine, Cytosine.
What type of reproduction creates offspring by generating a copy of the parent?
Asexual reproduction
What is a gene (simple one-sentence definition)?
A gene is a segment of DNA that codes for a trait or protein.
In which phase does the cell grow and do its normal jobs and also prepare for DNA replication?
Interphase
Name one visible change that happens during prophase.
Chromatin condenses and coils into visible chromosomes & spindle fibers form.
Define haploid in one sentence.
A haploid cell contains half the number of chromosomes (one set), e.g., 23 in humans.
What does DNA stand for?
Deoxyribonucleic Acid.
What type of asexual reproduction:
new organism grows from a large enough piece or a fragment of a its parent
Fragmentation
What is the difference between dominant and recessive alleles?
A dominant allele shows its trait when present; a recessive allele shows its trait only when two copies are present.
What happens during S-phase?
DNA is replicated (a perfect copy of genetic material is made).
Where do chromosomes line up during metaphase?
Along the metaphase plate (center of the cell).
How many total daughter cells are produced at the end of meiosis, and are they genetically identical or different?
Four daughter cells; they are genetically different from each other.
What is the shape of the DNA molecule (two-word answer)?
Double helix.
What is a single cell that results from the joining of the haploid gametes of the parents?
Zygote
What does homozygous mean? Give an example using letter notation (like "TT" or "tt").
Homozygous means two identical alleles for a trait, e.g., TT or tt.
During G2 phase what important check does the cell perform before mitosis?
The cell checks its newly made DNA for errors (DNA repair/checkpoints).
What structure pinches the animal cell in two during cytokinesis?
A cleavage furrow forms and deepens to pinch the cell in two.
What is crossing over and why does it matter for offspring?
Crossing over is the exchange of chromosome segments between homologous chromosomes during meiosis; it increases genetic variation.
Where does transcription take place?
in the nucleus
What are the two forms of sexual reproduction?
internal fertilization and external fertilization
State Mendel’s Law of Segregation in one sentence.
The Law of Segregation: allele pairs separate during gamete formation so each gamete carries only one allele for each gene.
Give two reasons why cells divide for the organism (name two different purposes).
to grow, to repair damaged tissue, and to reproduce cells
Explain how plant cytokinesis is different from animal cytokinesis (what structure forms in plant cells).
Plant cells form a cell plate between the two new cells instead of a cleavage furrow.
Contrast sexual vs. asexual reproduction by naming one advantage of each.
Sexual advantage: genetic diversity in offspring; Asexual advantage: only one parent needed and can be faster / less energy.
During translation, groups of three bases on mRNA that code for an amino acid are called what?
Codons
Why did God design so many different types of reproduction?
God designed multiple ways for reproduction to take place to allow organisms to continue to multiple, thrive, and survive in changing environments.
Explain codominance and give a simple example (one sentence).
Codominance: both alleles are expressed together (example: a roan cow with both red and white patches).