BI 121 Exam 2 - GRCC (Forbes) Questions
with Verified Answers 2026
Reproduction
The production of a new generation of cells or individuals
DNA
Deoxyribonucleic acid
A double-helix structure composed of nucleic acids which acts as the instructions or
template for the manufacture of proteins
Chromosome
A DNA molecule and the proteins associated with it
Bacteria does not have this
Genes (1 of 2)
A specific region of a DNA strand (or chromosome) that influences a certain inheritable
trait(s).
e.g., eye color, hair color
Gene Locus
Location of a gene on the chromosome
Somatic Cells
Those cells which comprise an organism's tissues and replicate by mitosis
Germ Cells
Those cells which will form gametes by meiosis
Zygote
The cell formed when two gametes fuse
Mitosis
A one stage nuclear division process in which he diploid number of chromosomes is
maintained in each of the daughter cells
Diploid Number (2n)
Having two chromosomes of each type, a pair of homologous chromosomes
23 paternal + 23 maternal = 46 total
BI 121- Anatomy and Physiology
,BI 121- Anatomy and Physiology
1. Replacement of cells - decrease with age
2. Growth in multi-cellular organisms
3. Asexual reproduction (when an egg and sperm come together - production of zygotes)
What are the functions of mitosis?
Production of diploid (2n) clones
What is the result of mitosis?
Interphase
Getting ready for mitosis (not actually a phase of mitosis)
Need to double chromosome number (46 x 2 = 96)
- bind together (fused by a centromere), making sister chromatids
Need to double organelle number
Spindle fibers are going to attach to sister chromatid to pull them apart
Prophase
Stage 1 of mitosis
Break apart nuclear membranes
See sister chromatids for the first time in a random formation (begin to condense)
Spindle fibers begin to form
Metaphase
Stage 2 of mitosis
Sister chromatids form a line in the middle
- "straight" line
Spindle fibers attach to sister chromatids
Anaphase
Stage 3 of mitosis
Chromosomes (what was the sister chromatids) move up toward the poled (to either side)
Form 2 rows
Telophase
Stage 4/Final stage of mitosis
Chromosomes have reached the poles - - end of journey
Cleavage furrow forms
Cytokenesis has begun (indication by formation of cleavage furrow)
Nuclear membrane begins to reform
Chromosomes begin to relax
- 46 chromosomes; 23 pairs
Cellular Differentiation
BI 121- Anatomy and Physiology
, BI 121- Anatomy and Physiology
All somatic cells contain the same genetic information, but they have the ability to
differentiate.
This decreases with age
Most cells are limited in their mitotic potential to approx. 50 divisions; they will no
longer go through mitosis after 50 divisions
e.g., muscle and most neurons
What are cells limited to?
Stem Cells
Undifferentiated cells that maintain ability to divide
What the cell is considered in the beginning
1. Telomeres
2. Kinases & Cyclins
3. Cell Size
4. Hormones
5. Growth Factors
6. Density Dependent Inhibition
7. Tumor Suppressor Genes
What are the factors influencing replication in cells?
Telomeres
Repeating nucleotide sequences at chromosome tips
Cells lose these every time they go through mitosis
Kinases & Cyclins
Intracellular proteins that control cell division
Cell Size
Division occurs to maintain favorable surface to volume ratio
Increase Surface Area
Hormones
E.g., prolactin, estrogen
Growth Factors
E.g., epidermal growth factor (EGF; produced in saliva)
Density Dependent Inhibition
Cell stops dividing when compressed against others
This is for all cells except cancer cells
BI 121- Anatomy and Physiology