2025 Biology Exam ACTUAL QUESTIONS
AND CORRECT ANSWERS
Normal Cells- - Correct answers✔Structure: even cell shape/size, one nucleus, normal
chromosome number
Function normally - can do the specific job the cell is designed to do
Can induced apoptosis (cell death) when damaged
Cancer Cells- - Correct answers✔Rapid uncontrolled growth (excessive growth)
Mutated signal tells the cells to divide when they shouldn't
Do not stop growing when in contact with other cells
Appearance: uneven cell shape/size, 1-3 nuclei, abnormal chromosome number
CANNOT induced apoptosis when damaged
Due to mutations in the DNA (tumor suppressor genes or DNA repair genes)
Many cancer cells lose their proper function
Leukemia
Cancer cells that end up pile up on one another form tumors - No contact inhibition.
Malignant cancer cells can migrate to other regions of the body
Cancer cells divide in less time than normal cells (CC =448 minutes vs. NC = 625 minutes)
Cancer cells do not differentiate. This means they do not become specialized cells (specialized
cells could be red blood cells, bone cells, skin cells, etc.)
This means that normal cells will differentiate (become specialized → examples include muscle
cell, skin cell, nerve (brain) cell)
Cancer cells do not maintain homeostasis
This means that normal cells do maintain homeostasis
Chromosomes: - Correct answers✔Chromosomes are tightly coiled strands of DNA
,DNA: Deoxyribonucleic Acid
Made of nucleotides
Humans have 46 strands of DNA, therefore 46 chromosomes appear in Mitosis for cellular
division
Histones - Correct answers✔proteins that allowed DNA to stay organized when coiling occurs
The Cell Cycle: - Correct answers✔Body cells divide for growth of an organism or repair of
damaged tissue. The two cells created are genetically identical to the original cell.
Interphase = G1, S, G2
Mitosis "nuclear division" = Prophase, Metaphase, Anaphase, Telophase (Pass me a taco)
Cytokinesis "cytoplasmic division"
TWO MAJOR EVENT OF INTERPHASE: - Correct answers✔Growth of the cell and cell parts
(increase in cytoplasm, increase in the number of organelles, etc)
Duplication (or Replication) of DNA (the DNA is copied) - see the differences in the red and
blue chromosomes at the beginning and end of interphase.
Interphase - Correct answers✔G1 - growth of the cell (organelles, proteins, cytoplasm)
S - synthesis of DNA (the creation of a second set of DNA = 2 identical copies) G2
- growth of the cell (organelles, proteins, cytoplasm)
Mitosis - Correct answers✔Prophase - chromosomes condense
Metaphase - chromosomes align at the center
Anaphase - sister chromatids separate
Telophase - chromosomes decondense
, Proto-oncogenes: - Correct answers✔regulatory proteins that stimulate the cell cycle
When the time is right (size of cell is appropriate and no DNA damage is present) these proteins
will tell the cell to continue through the cell cycle code for proteins that accelerate or stimulate
the cell cycle
Tumor Suppressor Genes: - Correct answers✔regulatory proteins that halt (stop) the cell cycle
(an example is the p53 gene)
When the cell is too small or there is damaged DNA these proteins will stop the cell cycle in
attempt to fix the problem.
If the errors cannot be corrected the cell will be programmed to go through apoptosis (cell death)
code for proteins to stop the cell cycle to fix DNA damage or for proteins to induce apoptosis
P53 - Correct answers✔is activated when a cell is stress, low in oxygen, has DNA damage, or is
exposed to chemotherapy.
→ p53 activates (or TURNS ON) other genes for expression - this mean that p53 causes other
proteins to be made
These proteins can be repair proteins (to fix DNA damage) or proteins that induce apoptosis (cell
death)
IF MUTATED, p53 cannot cause the creation of proteins to fix DNA or induce apoptosis
Chargaff's Rule aka "base pairing rule" - Correct answers✔states the percent of adenine equals
the percent of thymine AND the percent of guanine equals the percent of cytosine.
Adenine bonds to Thymine with TWO (2) hydrogen bonds
Guanine bonds to Cytosine with THREE (3) hydrogen bonds
A and G are called purines because they have a double ring structure
T and C are called pyrimidines because they have a single ring structure
AND CORRECT ANSWERS
Normal Cells- - Correct answers✔Structure: even cell shape/size, one nucleus, normal
chromosome number
Function normally - can do the specific job the cell is designed to do
Can induced apoptosis (cell death) when damaged
Cancer Cells- - Correct answers✔Rapid uncontrolled growth (excessive growth)
Mutated signal tells the cells to divide when they shouldn't
Do not stop growing when in contact with other cells
Appearance: uneven cell shape/size, 1-3 nuclei, abnormal chromosome number
CANNOT induced apoptosis when damaged
Due to mutations in the DNA (tumor suppressor genes or DNA repair genes)
Many cancer cells lose their proper function
Leukemia
Cancer cells that end up pile up on one another form tumors - No contact inhibition.
Malignant cancer cells can migrate to other regions of the body
Cancer cells divide in less time than normal cells (CC =448 minutes vs. NC = 625 minutes)
Cancer cells do not differentiate. This means they do not become specialized cells (specialized
cells could be red blood cells, bone cells, skin cells, etc.)
This means that normal cells will differentiate (become specialized → examples include muscle
cell, skin cell, nerve (brain) cell)
Cancer cells do not maintain homeostasis
This means that normal cells do maintain homeostasis
Chromosomes: - Correct answers✔Chromosomes are tightly coiled strands of DNA
,DNA: Deoxyribonucleic Acid
Made of nucleotides
Humans have 46 strands of DNA, therefore 46 chromosomes appear in Mitosis for cellular
division
Histones - Correct answers✔proteins that allowed DNA to stay organized when coiling occurs
The Cell Cycle: - Correct answers✔Body cells divide for growth of an organism or repair of
damaged tissue. The two cells created are genetically identical to the original cell.
Interphase = G1, S, G2
Mitosis "nuclear division" = Prophase, Metaphase, Anaphase, Telophase (Pass me a taco)
Cytokinesis "cytoplasmic division"
TWO MAJOR EVENT OF INTERPHASE: - Correct answers✔Growth of the cell and cell parts
(increase in cytoplasm, increase in the number of organelles, etc)
Duplication (or Replication) of DNA (the DNA is copied) - see the differences in the red and
blue chromosomes at the beginning and end of interphase.
Interphase - Correct answers✔G1 - growth of the cell (organelles, proteins, cytoplasm)
S - synthesis of DNA (the creation of a second set of DNA = 2 identical copies) G2
- growth of the cell (organelles, proteins, cytoplasm)
Mitosis - Correct answers✔Prophase - chromosomes condense
Metaphase - chromosomes align at the center
Anaphase - sister chromatids separate
Telophase - chromosomes decondense
, Proto-oncogenes: - Correct answers✔regulatory proteins that stimulate the cell cycle
When the time is right (size of cell is appropriate and no DNA damage is present) these proteins
will tell the cell to continue through the cell cycle code for proteins that accelerate or stimulate
the cell cycle
Tumor Suppressor Genes: - Correct answers✔regulatory proteins that halt (stop) the cell cycle
(an example is the p53 gene)
When the cell is too small or there is damaged DNA these proteins will stop the cell cycle in
attempt to fix the problem.
If the errors cannot be corrected the cell will be programmed to go through apoptosis (cell death)
code for proteins to stop the cell cycle to fix DNA damage or for proteins to induce apoptosis
P53 - Correct answers✔is activated when a cell is stress, low in oxygen, has DNA damage, or is
exposed to chemotherapy.
→ p53 activates (or TURNS ON) other genes for expression - this mean that p53 causes other
proteins to be made
These proteins can be repair proteins (to fix DNA damage) or proteins that induce apoptosis (cell
death)
IF MUTATED, p53 cannot cause the creation of proteins to fix DNA or induce apoptosis
Chargaff's Rule aka "base pairing rule" - Correct answers✔states the percent of adenine equals
the percent of thymine AND the percent of guanine equals the percent of cytosine.
Adenine bonds to Thymine with TWO (2) hydrogen bonds
Guanine bonds to Cytosine with THREE (3) hydrogen bonds
A and G are called purines because they have a double ring structure
T and C are called pyrimidines because they have a single ring structure
