AP BIOLOGY SEMESTER 1 FINALS REVIEW: UNITS 1-4 EXAM
QUESTIONS AND VERIDIED ANSWERS (2026/2027)
types of cell division - ANSWER-mitosis and meiosis
Mitosis - ANSWER-part of eukaryotic cell division during which the cell nucleus divides.
Responsible for growth and repair.
Diploid (2n) - ANSWER-two copies of each chromosome. complete genome
Meiosis - ANSWER-a type of cell division that results in four daughter cells each with
half the number of chromosomes of the parent cell, as in the production of gametes and
plant spores. Only occurs in sexually reproducing organisms.
Gametes - ANSWER-sex/reproductive cells
Haploid (n) - ANSWER-having a single set of unpaired chromosomes
sister chromatids - ANSWER-Replicated forms of a chromosome joined together by the
centromere and eventually separated during mitosis or meiosis II.
Centromere - ANSWER-Region of a chromosome where the two sister chromatids
attach
Kinetichore - ANSWER-structure surrounding centromere comprised of proteins where
spindle fibers attach
mitotic spindle (spindle fibers) - ANSWER-An assemblage of microtubules and
associated proteins that is involved in the movements of chromosomes during mitosis.
cell cycle - ANSWER-The regular sequence of growth and division that cells undergo
G-0 phase - ANSWER-A nondividing state occupied by cells that have left the cell cycle,
sometimes reversibly.
2 factors that promote cell division - ANSWER-Volume to surface area ratio, nucleus
capacity to control cell.
G1 phase - ANSWER-The first gap, or growth phase, of the cell cycle, consisting of the
portion of interphase before DNA synthesis begins. Cell size growth.
S phase - ANSWER-The synthesis phase of the cell cycle; the 2nd step of interphase
during which DNA is replicated.
,G2 phase - ANSWER-The second gap, or growth phase, of the cell cycle, consisting of
the portion of interphase after DNA synthesis occurs. Cell continues to grow in size and
prepare for cell division
Interphase - ANSWER-Cell grows, performs its normal functions, and prepares for
division; consists of G1, S, and G2 phases. More than 90% of a cell's life is in this stage.
Centrosome - ANSWER-A structure present in the cytoplasm of animal cells that
functions as a microtubule-organizing center and is important during cell division. A
centrosome has two centrioles.
microtubule organizing center (MTOC) - ANSWER-General term for any structure (e.g.,
centrosome and basal body) that organizes microtubules in cells. Can be found in both
animal & plant cells.
Prophase - ANSWER-first and longest phase of mitosis, during which the chromosomes
condense and become visible, the centrioles separate and take up positions on the
opposite sides of the nucleus while mitotic spindle begins to form. Nucleus begins to
dissolve.
Metaphase - ANSWER-second phase of mitosis, during which the chromosomes line up
across the center of the cell
Anaphase - ANSWER-the third phase of mitosis in which the chromosomes separate
and move to opposite ends of the cell
Telophase - ANSWER-the final phase of cell division in which the chromatids or
chromosomes move to opposite ends of the cell and two nuclei are formed.
Chromosomes unwind into chromatin.
Cytokinesis - ANSWER-division of the cytoplasm to form two separate daughter cells.
Happens right after mitosis.
cleavage furrow - ANSWER-the first sign of cytokinesis during cell division in an animal
cell; a shallow groove in the cell surface near the old metaphase plate
cell plate - ANSWER-A double membrane across the midline of a dividing plant cell,
between which the new cell wall forms during cytokinesis.
middle lamella - ANSWER-The thin film between the cell walls of adjacent plant cells.
contact inhibition/density dependent inhibition - ANSWER-the cessation of cell division
in response to contact with other cells
anchorage dependence - ANSWER-The requirement that to divide, a cell must be
attached to a solid surface.
, cancer cells - ANSWER-cells that grow and divide continuously at an unregulated pace.
Do not follow density-dependent or anchorage dependence rules.
cell cycle control system - ANSWER-A cyclically operating set of molecules, mostly
proteins, in the eukaryotic cell that both triggers and coordinates key events in the cell
cycle.
checkpoints in cell cycle - ANSWER-locations of cell division that can slow down the
process. Found in G1, G2, M
restriction point (R) - ANSWER-The point in the G1 stage where the cell is committed to
continue through the rest of the cell cycle and divide. (Some never reach this point,
entering a nondividing phase G0)
growth factors - ANSWER-Regulatory proteins that ensure that the events of cell
division occur in the proper sequence and at the correct rate. eg. PDGF
Cyclins - ANSWER-A group of proteins whose function is to regulate the progression of
a cell through the cell cycle and whose concentrations rise and fall throughout the cell
cycle. Synthesized during S and G2 phase.
Kinases - ANSWER-Enzymes that catalyze the transfer of phosphate groups from ATP
to acceptor molecules.
cyclin-dependent kinases (Cdks) - ANSWER-a regulatory protein that depends upon the
presence of cyclin to complete its function, MPF is a Cdk that triggers a cell's passage
into the M phase
Maturation Promoting Factor (MPF) - ANSWER-a cyclin-Cdk complex that triggers a
cell's passage past the G2 checkpoint into the M phase
Platelet-derived growth factor (PDGF) - ANSWER-One of the numerous proteins that
regulate the cell cycle. Stimulates division of smooth muscle cells and fibroblasts to
rebuild blood vessel wall (important in healing wounds)
Chemical signal pathways - ANSWER-often involve the binding of signal molecules to a
protein on the surface of a target cell
quorum sensing - ANSWER-The ability of bacteria to sense the presence of other
bacteria via secreted chemical signals.
gene expression - ANSWER-process by which a gene produces its product and the
product carries out its function
QUESTIONS AND VERIDIED ANSWERS (2026/2027)
types of cell division - ANSWER-mitosis and meiosis
Mitosis - ANSWER-part of eukaryotic cell division during which the cell nucleus divides.
Responsible for growth and repair.
Diploid (2n) - ANSWER-two copies of each chromosome. complete genome
Meiosis - ANSWER-a type of cell division that results in four daughter cells each with
half the number of chromosomes of the parent cell, as in the production of gametes and
plant spores. Only occurs in sexually reproducing organisms.
Gametes - ANSWER-sex/reproductive cells
Haploid (n) - ANSWER-having a single set of unpaired chromosomes
sister chromatids - ANSWER-Replicated forms of a chromosome joined together by the
centromere and eventually separated during mitosis or meiosis II.
Centromere - ANSWER-Region of a chromosome where the two sister chromatids
attach
Kinetichore - ANSWER-structure surrounding centromere comprised of proteins where
spindle fibers attach
mitotic spindle (spindle fibers) - ANSWER-An assemblage of microtubules and
associated proteins that is involved in the movements of chromosomes during mitosis.
cell cycle - ANSWER-The regular sequence of growth and division that cells undergo
G-0 phase - ANSWER-A nondividing state occupied by cells that have left the cell cycle,
sometimes reversibly.
2 factors that promote cell division - ANSWER-Volume to surface area ratio, nucleus
capacity to control cell.
G1 phase - ANSWER-The first gap, or growth phase, of the cell cycle, consisting of the
portion of interphase before DNA synthesis begins. Cell size growth.
S phase - ANSWER-The synthesis phase of the cell cycle; the 2nd step of interphase
during which DNA is replicated.
,G2 phase - ANSWER-The second gap, or growth phase, of the cell cycle, consisting of
the portion of interphase after DNA synthesis occurs. Cell continues to grow in size and
prepare for cell division
Interphase - ANSWER-Cell grows, performs its normal functions, and prepares for
division; consists of G1, S, and G2 phases. More than 90% of a cell's life is in this stage.
Centrosome - ANSWER-A structure present in the cytoplasm of animal cells that
functions as a microtubule-organizing center and is important during cell division. A
centrosome has two centrioles.
microtubule organizing center (MTOC) - ANSWER-General term for any structure (e.g.,
centrosome and basal body) that organizes microtubules in cells. Can be found in both
animal & plant cells.
Prophase - ANSWER-first and longest phase of mitosis, during which the chromosomes
condense and become visible, the centrioles separate and take up positions on the
opposite sides of the nucleus while mitotic spindle begins to form. Nucleus begins to
dissolve.
Metaphase - ANSWER-second phase of mitosis, during which the chromosomes line up
across the center of the cell
Anaphase - ANSWER-the third phase of mitosis in which the chromosomes separate
and move to opposite ends of the cell
Telophase - ANSWER-the final phase of cell division in which the chromatids or
chromosomes move to opposite ends of the cell and two nuclei are formed.
Chromosomes unwind into chromatin.
Cytokinesis - ANSWER-division of the cytoplasm to form two separate daughter cells.
Happens right after mitosis.
cleavage furrow - ANSWER-the first sign of cytokinesis during cell division in an animal
cell; a shallow groove in the cell surface near the old metaphase plate
cell plate - ANSWER-A double membrane across the midline of a dividing plant cell,
between which the new cell wall forms during cytokinesis.
middle lamella - ANSWER-The thin film between the cell walls of adjacent plant cells.
contact inhibition/density dependent inhibition - ANSWER-the cessation of cell division
in response to contact with other cells
anchorage dependence - ANSWER-The requirement that to divide, a cell must be
attached to a solid surface.
, cancer cells - ANSWER-cells that grow and divide continuously at an unregulated pace.
Do not follow density-dependent or anchorage dependence rules.
cell cycle control system - ANSWER-A cyclically operating set of molecules, mostly
proteins, in the eukaryotic cell that both triggers and coordinates key events in the cell
cycle.
checkpoints in cell cycle - ANSWER-locations of cell division that can slow down the
process. Found in G1, G2, M
restriction point (R) - ANSWER-The point in the G1 stage where the cell is committed to
continue through the rest of the cell cycle and divide. (Some never reach this point,
entering a nondividing phase G0)
growth factors - ANSWER-Regulatory proteins that ensure that the events of cell
division occur in the proper sequence and at the correct rate. eg. PDGF
Cyclins - ANSWER-A group of proteins whose function is to regulate the progression of
a cell through the cell cycle and whose concentrations rise and fall throughout the cell
cycle. Synthesized during S and G2 phase.
Kinases - ANSWER-Enzymes that catalyze the transfer of phosphate groups from ATP
to acceptor molecules.
cyclin-dependent kinases (Cdks) - ANSWER-a regulatory protein that depends upon the
presence of cyclin to complete its function, MPF is a Cdk that triggers a cell's passage
into the M phase
Maturation Promoting Factor (MPF) - ANSWER-a cyclin-Cdk complex that triggers a
cell's passage past the G2 checkpoint into the M phase
Platelet-derived growth factor (PDGF) - ANSWER-One of the numerous proteins that
regulate the cell cycle. Stimulates division of smooth muscle cells and fibroblasts to
rebuild blood vessel wall (important in healing wounds)
Chemical signal pathways - ANSWER-often involve the binding of signal molecules to a
protein on the surface of a target cell
quorum sensing - ANSWER-The ability of bacteria to sense the presence of other
bacteria via secreted chemical signals.
gene expression - ANSWER-process by which a gene produces its product and the
product carries out its function
