JLaurence Guieb XII - Fermions

General Biology Reviewer

CELL CYCLE

Cell Cycle - repeating sequence of Cell Growth (G1) Checkpoint - makes

cellular growth and division; 90% time the decision whether the cell will divide
for first three(3) phases - interphase or not; cell must be healthy or large
enough; protein will stimulate the cell to
Five(5) Phases of the Cell Cycle start synthesis; it will stop if the cell
1. First Growth Phase (G1) needs to pass into resting period.
2. Synthesis (S)
3. Second Growth Phase (G2) Nerve cells never grow, they only
4. Mitosis degenerate.
5. Cytokinesis
DNA Synthesis (G2) Checkpoint -
First Growth Phase (G1) - Cell DNA replication is checked by DNA
grows rapidly and carries out its routine repair enzymes; proteins have to trigger
function; preparation of DNA the mitosis if passed.
replication; duplication of cellular
components. Mitosis Checkpoint - Triggers exit
from mitosis; signals beginning G!
Synthesis (S) - Cell DNA is copied; Phase.
each chromosome will consist two(2)
chromatids attached on the centromere. If control is lost, the proteins may not
function; The process might be
Second Growth Phase (G2) - disrupted.
preparation are made for the nucleus to Cancer - uncontrolled growth of cells.
divide; preparation state.

Mitosis - separation of the nuclei;

nucleus separates into two nuclei; REGULATION OF CELL CYCLE
division of somatic cells - all cells
except sex cells Cell cycle regulation is necessary for
healthy growth.
Prophase
Metaphase Internal And External Factors
Anaphase Regulate Cell Division.
Telophase
- External factors include physical and
Cytokinesis - Cytoplasm divides; cell chemical signals.
slowly elongates. Cleavage furrow - - Growth factors are proteins that
animal cell; Cell plate - plant cells stimulate cell division.
- Most mammal cells form a single
Cells have a set of “red light - green layer in a culture dish and stop dividing
light” switches. once they touch other cells.
Cells have (inspection - Two of the most important internal
points). factors are kinases and cyclins.
JLaurence Guieb XII - Fermions

External factors trigger internal factors, UNCONTROLLED MITOSIS

which affect the cell cycle.
-If mitosis is not controlled, unlimited
Apoptosis is programmed cell death. cell division occurs causing cancerous
tumors.
-a normal feature of healthy organisms -Oncogenes are special proteins that
-caused by a cell’s production of increase the chance that a normal cell
self-destructive enzymes develops into a tumor cell.
-occurs in development of infants
MEIOSIS - Formation of Gametes
Cell division is uncontrolled in cancer. (Eggs & Sperm)

-Cancer cells form disorganized clumps Preceded by interphase which

called tumors. includes chromosome replication
-Benign tumors remain clustered and
can be removed. Two meiotic divisions --- Meiosis
-Malignant tumors metastasize, or break I and Meiosis II
away, and can form more tumors.
Called Reduction- division

Original cell is diploid (2n)

Four daughter cells produced that

are monoploid (1n)
Cancer cells do not carry out necessary
Daughter cells contain half the
functions.
number of chromosomes as the
Cancer cells come from normal cells
original cell
with damage to genes involved in
cell-cycle regulation.
Produces gametes (eggs & sperm)
Carcinogens are substances known to
promote cancer.
Occurs in the testes in males
Standard cancer treatments typically kill
(Spermatogenesis)
both cancerous and healthy cells.
Occurs in the ovaries in females
(Oogenesis)

Start with 46 double stranded

chromosomes (2n)

After 1 division - 23 double

stranded chromosomes (n)

After 2nd division - 23 single

stranded chromosomes (n)

Occurs in our germ cells that

produce gametes
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Why do we need Meiosis? Meiosis Forms Haploid Gametes

-It is the fundamental basis of - Meiosis must reduce the chromosome

sexual reproduction number by half

-Two haploid (1n) gametes are - Fertilization then restores the 2n

brought together through number
fertilization to form a diploid
(2n) zygote

Fertilization

Meiosis: Two Part Cell Division

Replication of Chromosomes

Meiosis I: Reduction Division

Replicated Chromosome
JLaurence Guieb XII - Fermions
JLaurence Guieb XII - Fermions

Gametogenesis
Oogenesis or Spermatogenesis
JLaurence Guieb XII - Fermions

TRANSPORT MECHANISM

Membrane Transport
- Collection of mechanisms that
regulate the passage of solutes
- Selective membrane
permeability
- Can be permeable to certain
substances but not to others
- Mediated by membrane
transport proteins
- Group of specific transport
proteins for each cell type and
for every specific physiological
stage
JLaurence Guieb XII - Fermions

Passive Vs. Active Transport

Passive
- Does not require energy
- Molecules moves from higher
concentration to lower
Concentration.

Active
-Does require energy BIOLOGICAL
-Molecules moves from region of MACROMOLECULES
low concentration to high -Large Molecule
concentration. -Organic
- Hydrocarbons

Four Classes of Biological

Macromolecules
1. Proteins
2. Lipids
3. Carbohydrates
4. Nucleic Acids

Polymers - poly(many)
-made up of single units called
monomers

Carbohydrates (C,H,O)

Simple Carbohydrates
- They are the main source of energy for
the body
- Simple sugars >> Monosaccharide
- Glucose, for example, is the main
product of photosynthesis!!

Complex Carbohydrates
-Long-term storage for energy
-Polysaccharides >> made up of glucose
polymers

Starch
- Grains (wheat, rice, corn, oats, barley)
- Tubers such as potatoes are rich in
starch.
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Cellulose PhosphoLIPID bilayer of the cell

- ALSO a glucose polymer membrane? The fatty acid tails are
- Offers the plant support lipids!
- Energy storage
- Makes up cell wall It’s semi-permeable, allowing only
- Food source for certain molecules to diffuse across the
seeds and plant bulbs membrane to enter or exit the cell.

Glycogen in Animals Triglyceride >> Glycerol Group with 3

-A branched polymer made up of Fatty Acid Chains
numerous glucose monomers
-Long-term energy storage found in the Proteins
liver - They are the major structural
-Quickly broken down into glucose for molecules in living things for growth
immediate energy and repair : muscles, ligaments, tendons,
bones, hair, skin, nails…IN FACT ALL
Complex Carbs and Energy - CELL MEMBRANES have protein in
- Starches, Cellulose and Glycogen are them.
broken down by proteins called enzymes - They make up antibodies in the
- Broken down into their monomers >> immune system.
Glucose - They make up enzymes for helping
-Glucose is further broken down during chemical reactions.
cellular respiration in the mitochondria - They makeup non-steriod hormones
for energy which.
- About 36 ATP molecules of energy
each glucose molecule!!! THINK: Proteins >> membranes,
enzymes, antibodies, non-steriod
Lipids (C,H, and few O) hormones, structural molecules,
“MEANS”
- STORED ENERGY Broken down
for energy -C, H, O, and N (Some Sulfur)
- They INSULATE the body to help -Made up of Amino Acid Monomers
maintain normal body temperature and - A peptide bond bonds amino acids
they CUSHION the internal organs for together
protection. - Creates a polypeptide
- Include waxes, Oils
- include steroids such as cholesterol and Insulin
the sex hormones estrogen and - Chemical signaler protein produced in
testosterone the pancreas
- Anabolic steroids build muscle - Causes cells in the liver, muscle, and
- They waterproof surfaces of animals, fat tissue to take up glucose from blood
plants, and fruits- these are waxes! and convert it to glycogen that can be
stored in the liver and muscles
THINK: Waterproof, insulate, steroids, - Diabetes is a condition when a person
energy, cushion… has high blood glucose (blood sugar),
either because insulin production is
inadequate, or because the body's cells
do not respond properly to insulin, or
both.
JLaurence Guieb XII - Fermions

CELL DIVISION
Hemoglobin
-All cells are derived from
Antibodies pre-existing cells
- Antibodies are part of the immune -New cells are produced for
system. growth and to replace damaged
- When something enters the body that or old cells
isn’t supposed to be there, like certain -Differs in prokaryotes (bacteria)
bacteria, antibodies find the invader and and eukaryotes (protists, fungi,
stick themselves onto it. plants, & animals)
- White Blood cells destroy the invaders.
DNA Replication
Enzymes -DNA must be
- Speed up the rate of a chemical copied or
reaction (a catalyst) by lowering the replicated
energy needed to begin the reaction before cell
(Below) division
- Re-usable -Each new cell
- Molecule specific – like a lock and key will then have an
-Example: ONLY Lactase will identical copy of
break down lactose. It will NEVER the DNA
break down proteins
Mitosis
- Division of the nucleus
- Also called karyokinesis
- Only occurs in
eukaryotes
- Has four stages
- Doesn’t occur in
some cells such
as brain cells

Early Prophase

pH Affects Enzyme Reactivity(pH - Chromatin in nucleus condenses to

Level 4) form visible chromosomes
- Mitotic spindle forms from fibers in
Nucleic Acids cytoskeleton or centrioles (animal)

The types of Nucleic Acids Late Prophase

DNA (DeoxyriboNucleic Acid) -Nuclear membrane & nucleolus are

broken down
RNA (RiboNucleic Acid) -Chromosomes continue condensing
& are clearly visible
- Monomers are called Nucleotides -Spindle fibers called kinetochores
attach to the centromere of each
chromosome
JLaurence Guieb XII - Fermions

-Spindle finishes forming between - In plant cells, cell plate forms

the poles of the cell at the equator to divide cell
- In animal cells, cleavage furrow
Spindle Fibers forms to split cell

-The mitotic spindle form from the Daughter Cells of Mitosis

microtubules in plants and
centrioles in animal cells - Have the same number of
-Polar fibers extend from one pole chromosomes as each other and
of the cell to the opposite pole as the parent cell from which
-Kinetochore fibers extend from they were formed
the pole to the centromere of the - Identical to each other, but
chromosome to which they attach smaller than parent cell
-Asters are short fibers radiating - Must grow in size to become
from centrioles mature cells (G1 of Interphase)

Metaphase

-Chromosomes, attached to the

kinetochore fibers, move to the center
of the cell
-Chromosomes are now lined up at the
Equator

Anaphase

-Occurs rapidly
-Sister chromatids are pulled apart to
opposite poles of the cell by kinetochore
fibers

Telophase

-Sister chromatids at opposite

poles
-Spindle disassembles
-Nuclear envelope forms around
each set of sister chromatids
-Nucleolus reappears
- CYTOKINESIS occurs
- Chromosomes reappear as Chromatin

Cytokinesis
-Means division of the cytoplasm
- Division of cell into two,
identical halves called daughter
cells