Domain 1-Cells and Heredity Student Notes
I. The cell is the basic unit of all living things.
A. There are 2 basic types of cells:
1. Eukaryotic cells have a true nucleus and
organelles. All plants, animals, fungi, and protists are
eukaryotes.
2. Prokaryotic cells do not have a true
nucleus or organelles. Examples of prokaryotes are bacteria.
Single chromosome
Prokaryotic cell
Eukaryotic Cell
B. Parts of the cell-need to know terms
1. Nucleus - controls cell functions (the brain); contains the DNA
2. Cell membrane - regulates the movement of water, nutrients and
wastes into and out of the cell
(gatekeeper; communicator)
3. Endoplasmic reticulum - is responsible for the transport of molecules from one
part of the cell to another..
4. Ribsome - site of protein synthesis; where proteins are made
5. Mitochondria - provide the energy a cell needs for all its activities;
site of cellular respiration
6. Chloroplast - site of photosynthesis
7. Lysosome - contains digestive enzymes that break down worn-out
cells and cell parts.
8. Golgi apparatus- The Golgi apparatus modifies, sorts, and
packages macromolecules for transport out of the cell or for use within the cell.
9. Vacuole - membrane bound sac that stores nutrients or water. Vacuoles are large
in plant cells and play a role in turgor pressure (the stiffening of a plant due to
water)
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10. Cell wall - rigid non-living outer wall of some cells which is made of cellulose
(plants) or chitin (fungi)
11. Cytoskeleton - made of microtubules which help to maintain cell shape and
function in internal movement of cell organelles
12. helps to main cell shape and is important in internal movement of cell organelles
13. Cytoplasm - jellylike substance that fills the inside of a cell
Label the cells and parts indicated.
1. Which part (s) are present only in a plant cell?
cell wall, chloroplasts
2. Which part (s) are present only in an animal cell?
centriole
C. Cell Chemistry Macromolecules
Macromolecules
Building Blocks or
smaller units
monosaccharides
1. Carbohydrates
2. Lipids
fatty acids and
glycerol
Uses
primary source of energy
store energy efficiently
part of cell membrane
amino acids
3. Proteins
growth and repair, enzymes
nucleotides
4. Nucleic Acids
genetic information
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D. What is Homeostasis?
1. Homeostasis - self-adjusting mechanism that helps to maintain your
internal environment
2. maintenance of a steady internal environment in face of a changing
external environment (example: temperature-body sweats, fever flush)
3. Materials must be transported into and out of the cell to
maintain homeostasis.
E. Types of Transport
1. Passive transport is the movement of materials that does NOT require energy.
Diffusion, osmosis and facilitated diffusion are examples of passive transport.
a. Diffusion - is the movement of ions or molecules from regions
of higher concentration to regions of lower concentration. (Down a
concentration gradient)
b. Osmosis - diffusion of water across a semi-permeable membrane
2. Active transport requires the use of energy usually from
ATP, a compound in which energy is stored in living systems. Active
transport "pumps" materials across the membrane against the concentration
gradient (from low concentration to high concentration and therefore
requires energy.)
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E. Cell Environment
Isotonic Environment
The water and solute
concentration are same inside
and outside the cell. Water goes
in and out at the same rate.
Hypotonic Environment
The water concentration is greater
outside the cell; the solute
concentration is greater inside the cell.
Water flows into the cell.
Hypertonic Environment
The water concentration is greater
inside the cell; the solute
concentration is greater outside the cell.
Water flows out of the cell.
II. Cell Energy
A. Photosynthesis
1. starts with carbon dioxide, CO2 and water, plus sunlight
2. ends with glucose (sugar), C6H12O6 and oxygen,O2
3. stores energy from sunlight in the sugar glucose
4. occurs in the chloroplasts
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B. Respiration
1. starts with glucose (sugar), C6H12O6 and oxygen
2. ends with carbon dioxide, CO2, water, and ATP (energy molecule)
3. takes energy from glucose and uses it to run the cell’s processes
4. occurs in the mitochondria
C. Comparison of photosynthesis and respiration.
Photosynthesis
sunlight
6 CO2 + 6H2O

C6H12O6 + 6O2
chlorophyll
Respiration
C6H12O6 + 6 O2  6 CO2 + 6 H2O + energy
Reaction Type
Energy Source
Form of Energy produced
Reactants
Products
Respiration
Exothermic
releases energy
Photosynthesis
Endothermic
absorbs energy
Glucose
Light
ATP
Glucose
O2, glucose
CO2, H2O, energy
CO2, H2O
O2, glucose
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III. Cell Reproduction
A. Interphase
o cell growth period
o replication (copying) of DNA
B. Mitosis - reproduction of regular (body, somatic) cells.
1. Prophase (DNA coils, spindle fibers appear)
2. Metaphase (Chromosomes line up at the middle of the cell)
3. Anaphase (chromatids separate and are pulled to opposite sides of the
cell)
4. Telophase (spindle fibers disappear, cell cytoplasm divides in twocytokinesis)
5. daughter cells have the same number and kind of
chromosomes as parent cell (2n)
C.
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Meiosis-production of sex cells (gametes)
1. cell goes through same phases as mitosis but twice
2. in a second division, chromosome number is halved (n)
3. daughter cells have half the number of chromosomes as parent cell
D. Chromosomes are made of
DNA - deoxyribonucleic acid
1. located in the nucleus
2. made of nucleotides, which are composed of phosphate groups,
deoxyribose sugars, and (nitrogen-containing) bases
3. bases - adenine, guanine, cytosine, and
thymine
adenine pairs with thymine (A-T)
guanine pairs with cytosine (G-C)
4. shape of DNA is a double helix (twisted ladder); double stranded
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RNA
1. made of nucleotides- phosphate groups, and ribose sugars, and bases
2. bases-same as DNA except thymine is replaced by uracil
adenine pairs with uracil (A-U)
guanine pairs with cytosine (G-C)
3. single - stranded
4. three types-messenger RNA, mRNA, transfer RNA, tRNA,
ribosomal RNA, rRNA
Protein synthesis
Cell membrane
1. Transcription - occurs in the
nucleus, messenger RNA
copies the DNA code, then
mRNA leaves the nucleus
2. Translation - occurs on the
ribosomes, transfer RNA brings the
nucleotides to the ribosome so that the
correct protein can be synthesized
IV. Genetics and Heredity
A. Heredity - study of the passing of traits from parent to offspring.
1. allele - gene forms ex T-tall or t-short
2. traits
a. dominant - trait that is seen or that overrides the rest (T)
b. recessive (t)
3. phenotype - the way an organism looks; the expression of a trait
ex. Tall, short
4. genotype - the actual gene make-up ex TT, Tt, tt
5. homozygous - trait with the same alleles (TT, tt)
6. heterozygous - trait with different alleles (Tt)
7. offspring - children
8. Monohybrid Cross-a parental cross of one trait.
9. Punnett square-used to determine the results of a cross
between two parents
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What are the possible genotype and phenotype of the offspring of a cross
between two heterozygous parents?
Tt X Tt
T
T
t
Genotype
t
TT
Tt
Tt
tt
¼ TT, ½ Tt, ¼ tt or 1:2:1
Phenotype ¾ tall, ¼ short
C. Incomplete or Blended Dominance-neither gene is dominant
RR=red flower
RW=pink flower
WW=white flower
What are the possible genotype and phenotype of the offspring of a cross between
two heterozygous parents?
R
R
W
W
RR
RW
RW
WW
Genotype
¼ RR, ½ RW, ¼ WW
Phenotype
¼ red, ½ pink, ¼ white
Taxonomy
Taxonomy is the classification of organisms.
1. Today all living things are divided into 6 kingdoms.
2. This classification is based on physical similarities as well as
evolutionary relationships such as how organisms develop, DNA sequences, and
protein similarities.
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Viruses
1. Viruses are NOT living organisms.
2. Viruses need a living cell to reproduce.
Archaebacteria Eubacteria
“ancient
“new
bacteria”
bacteria”
Protists
Thermophiles,
halophiles,
methanogens
green algae,
E. coli,
Streptococcus diatoms,
Cell Level
Cell Type
Prokaryote
Unicellular
Prokaryote
Unicellular
Nutrition
Autotrophs
Transport
Simple diffusion
Heterotrophs,
decomposers,
autotrophs
Simple
diffusion
Examples
Amoeba,
Paramecium
Eukaryote
Unicellular
(some algae
are
multicellular)
Heterotrophs
(algae are
autotrophs)
Diffusion
(specialized
organelles
move
materials)
Fungi
Plants
Molds,
mushrooms,
yeasts
grasses,
pine trees,
rose
bushes,
mosses
Eukaryote
Multicellular
Eukaryote
Multicellular
(yeasts are
unicellular)
Animals
(invertebrates
and
vertebrates)
insects,
worms,
sponges,
Reptiles,
mammals
Eukaryote
Multicellular
Heterotrophs, Autotrophs
decomposers
Heterotrophs
Connected
cells called
hyphae
move
materials
Vascular
systems
(vertebrates)
Most have
vascular
tissue
(xylem
moves
water and
phloem
moves
food)
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