DNA
Adenine - Thymine
Guanine - Cytosine
How do cells created from mitosis compare to each other?
They are genetically identical
All cells in a multicellular organism generally contain —
A. Different DNA
B. Identical DNA
C. No DNA
D. Only RNA
B — Identical DNA
Nearly all somatic cells in an organism contain identical DNA.
Differences arise from gene expression, not different DNA.
Cancer is best described as
Rapid and uncontrolled cell division
Cancer results from failure of cell cycle regulation.
It is the opposite of controlled division.
Which phase of the cell cycle involves cell growth and normal metabolic activity?
B - Interphase
Interphase (G₁, S, G₂) is when the cell grows, performs normal functions, and replicates DNA.
Part 1: Name 3 scientists responsible for discovering the structure of DNA
Part 2: What is the name of the structure?
1. Franklin, Watson and Crick
2. Double helix
9. Mitosis is most directly responsible for —
A. Genetic variation
B. Growth and tissue repair
C. Formation of gametes
D. Reduction of chromosome number
B. Growth and tissue repair
Ex. paper cut, closing quick with new skin cells only at the site of cut
Cell differentiation results in cells that —
A. Have identical functions
B. Perform specialized functions
C. Divide continuously
D. Contain different DNA
B. Perform specialized functions
Differentiation results in specialized structure and function.
All cells maintain the same DNA (so D is incorrect).
A mutation in a gene that regulates the cell cycle is most likely to result in —
A. Faster DNA replication accuracy
B. Uncontrolled cell division
C. Cell differentiation
D. Increased checkpoints
B — Uncontrolled cell division
Mutations in regulatory genes (e.g., tumor suppressor genes) remove cell cycle control.
A and D would prevent cancer, not cause it.
DNA replication occurs during which phase?
S
DNA replication occurs during the S (Synthesis) phase of interphase.
G₁ is growth.
G₂ prepares for mitosis.
M phase is division.
Name the 3 parts of a DNA nucleotide
1. deoxyribose (sugar)
2. phosphate
3. nitrogen base
New cells created through mitosis are called _______ cells.
Daughter cells
What causes cells with identical DNA to become different types of cells?
A. Loss of chromosomes
B. Different genes being expressed
C. Different numbers of mitochondria
D. DNA mutations
B — Different genes being expressed
Cell differentiation is driven by selective gene expression.
Cells do not lose chromosomes (A) or require mutation (D) to specialize.
If DNA replication errors are not corrected before mitosis, what is the most likely outcome?
A. Faster cell growth
B. Genetic mutations passed to daughter cells
C. Immediate cell death
D. Increased protein production
B — Genetic mutations passed to daughter cells
Uncorrected replication errors become mutations that are inherited by daughter cells.
A and D do not logically result from replication errors.
C is possible but not the most likely outcome.
During which stage of mitosis do chromosomes line up at the cell’s equator?
Metaphase
During metaphase, chromosomes align at the cell’s equator (metaphase plate).
Prophase = chromosomes condense.
Anaphase = chromatids separate.
Telophase = nuclei reform.
DNA replication is semiconservative. Why is that?
Each strand is comprised of one old strand and one new strand
Why is DNA replication necessary before mitosis?
Replication ensures each daughter cell receives identical genetic information.
Name a place in adults where the most stem cells are found
Bone marrow
A substance or agent directly linked to causing cancer is called a/an
Carcinogen
Cytokinesis results in —
Division of the cytoplasm
ending of cycle - when one cells successfully splits into two identical cells due to division
If a DNA strand has 13% Adenine nucleotides, how many Guanine nucleotides does it have?
37%
Why are stem cells important in development?
They can differentiate into multiple cell types
Environmental factors can influence cell differentiation by —
Affecting gene expression
Environmental factors influence which genes are activated or silenced.
Which situation would most likely lead to cancer development?
A. Proper checkpoint function
B. DNA repair mechanisms working correctly
C. Failure of cell cycle checkpoints
D. Controlled apoptosis
C — Failure of cell cycle checkpoints
Cancer develops when checkpoints fail and damaged cells continue dividing.
A, B, and D represent normal protective mechanisms.
A cell detects DNA damage during the G₁ checkpoint. The damage cannot be repaired.
What will most likely occur?
A. The cell continues to divide
B. The cell enters apoptosis
C. The cell skips S phase
D. The cell increases ATP production
B — The cell enters apoptosis