Unit 6 Study Guide: https://quizlet.com/_1e45j5
Unit 6 Notes:
Unit 6: Cell Structure and Function CONCISE
Notes
1.
Cell – the basic units of structure and function
in living things.
a. The
smallest unit that can carry out life processes.
b. Size
range from 30 meters long (neuron cell in a blue whale) to 0.2 micrometers long
(smallest bacteria)
c. All
cells have a cell membrane, cytoplasm, and DNA
2.
Cell History
a. The
invention of the microscope made it possible for people to observe cells
b. Robert
Hooke – first to observe cells – cork and fern stems
i.
Coined the term cells because of their shape
c. Anton
Van Leeuwenhoek – first to observe living cells – protists (animalcules)
d. The
Cell Theory
i.
All living things are made of cells
ii.
Cells are the basic unit of living things
iii.
Cell come only from other cells
iv.
Scientists who helped form the cell theory:
1. Matthias
Schleiden – discovered that all plants were made of cells
2. Theodore
Schwann – discovered that all animals were made of cells
3. Rudolph
Virchow – concluded that all cells come from other living cells
3.
Kinds of Cells
a. Prokaryotic
cells
i.
No nucleus
ii.
No membrane bound organelles
1. Do
have ribosomes and DNA
iii.
Always unicellular
iv.
Ex. Bacteria
b. Eukaryotic
Cells – more advanced, complex cells
i.
Have nucleus
ii.
Have membrane bound organelles
iii.
Maybe unicellular or multicellular
iv.
Ex. Plants, Animals, Fungi, Protists
4.
Organelles (little organ) – structures in a cell
that carry out specific functions
a. Cell
Membrane (plasma membrane) (see Unit 7)
i.
Found in all cells, prokaryotic and eukaryotic
ii.
Structure - Phospholipid bilayer
a. Two
layers, a lipid tail and a phosphate head
iii.
Function – controls what enters and leaves a
cell
1. Selectively
permeable – allows some but not all molecules to enter the cell
a. Water
may enter and leave freely
b. Sodium
and Calcium for example must enter through certain channels at certain times
2. Helps
maintain a cell’s homeostasis (stable internal conditions)
b. Cell
Wall
i.
Found in plant, algae, fungi, and most bacterial
cells
ii.
Located outside of the cell membrane
iii.
Structure
1. Plants
– made of cellulose, a kind of carbohydrate
2. Fungi
– made of chitin, a different kind of carbohydrate
iv.
Function – protects, supports, and shapes the
cell
1. Does
not help determine what enters and
leaves a cell
2. Allows
the stems of plants to stand upright
3. Prevents
plant from expanding under pressure
c.
Nucleus
i.
Found in eukaryotic cells
ii.
Structure - Usually the largest organelle
1. Nuclear
envelope (nuclear membrane) surrounds the nucleus
2. Nuclear
pores (holes) that allow RNA and ribosomes to enter and leave the nucleus
3. Nucleolus
- inside the nucleus and makes ribosomes
4. DNA
is inside the nucleus
a. A
component of chromatin
b. Condenses
into chromosomes during mitosis and meiosis
c. Directions
for making proteins
iii.
Function – control center – directs all of the
cells activities
d. Cytoplasm
(protoplasm)
i.
Found in prokaryotic and eukaryotic cells
ii.
Structure - Clear, jelly-like material surrounding organelles
1. Constantly
flows
iii.
Function - Holds organelles
1. Most
metabolic processes occur in the cytoplasm
e. Endoplasmic
Reticulum (ER)
i.
Found in eukaryotic cells
ii.
Structure - A series of folded membranes on and
around the nucleus (H’s connected
together)
iii.
Function - Move proteins and other materials
around the cell similar to a conveyor belt
iv.
Types
1. Smooth
ER (sER) – few or no ribosomes
2. Rough
ER (rER) – covered in ribosomes
f.
Ribosomes (rRNA) - (Unit 12)
i.
Found in prokaryotic and eukaryotic cells freely
floating or attached to ER
ii.
Structure - Small and round (small black dots); made of RNA (rRNA)
iii.
Function - Help build proteins
g. Golgi
Body (Golgi Complex; Golgi Apparatus)
i.
Found in eukaryotic cells
ii.
Structure - Flattened, folded sacs (Q-tips with circles around them)
iii.
Function - Sort and package materials like
proteins
1. Packages
materials to be sent out of the cell
h. Vacuoles
and Vesicles
i.
Found in eukaryotic cells
1. Plant
cells usually have one large vacuole
2. Animal
cells usually have many small vacuoles
ii.
Structure - Sac-like structure
iii.
Function - Store materials like water, food, and
waste
i.
Mitochondria (see Unit 8)
i.
Found in eukaryotic cells
1. Muscle
cells contain up to 20,000 mitochondria each
ii.
Structure - Hot-dog shaped (a jelly bean with a worm on the inside)
1. Outer
membrane and a folded inner membrane called cristae
iii.
Function - Break down food molecules and produce
ATP, a high energy compound
j.
Cytoskeleton
i.
Found in prokaryotic and eukaryotic cells
ii.
Structure - Thin tubes called microtubules and
fibers microfilaments
1. Made
of protein
iii.
Function - Help cell maintain and change its
shape
1. Most
organelles are attached to it
2. Help
move chromosomes in cell division (spindle fibers)
k. Centrioles
i.
Found only in animal cells
ii.
Structure - Cylinder shaped
1. Two
centrioles along with proteins make up the centrosome
iii.
Function - help in the
formation of the spindle fibers that separate the chromosomes during cell
division
l.
Cilia and Flagella
i.
Structure
1. Cilia - short, hairlike, move liquids such as mucus past the cell or
moves unicellular organisms
2. Flagella - whip-like, longer than cilia moves cells such as the human
sperm
ii.
Function - help in
movement or feeding
m. Lysosomes
i.
Found in eukaryotic cells
ii.
Structure - Round
organelle that contains enzymes
iii.
Function - Digest
unwanted food particles, bacteria, and other debris
n.
Plastids
i.
Found in plant cells
ii.
Types
1. Chromoplasts
a. Structure - red, yellow or orange in color and are found in
petals of flowers and in fruit
b. Function
– to attract pollinators (petals )and animals that will help disperse seeds
(fruits)
2. Leucoplasts
a. Structure – colorless, occur in plant cells not exposed to
light, such as roots and seeds
b. Function
– form starches; help form proteins and oils
i.
Amyloplasts make starches and change
starches back to glucose when needed
3. Chloroplasts
a. Found
in certain eukaryotic cells
b. Plants,
protists, cyanobacteria (blue-green algae) do not have chloroplasts, but do
have two cell membranes and carry out photosynthesis
c. Structure
- Outer membrane with stacked sacs (sacs called thylakoid, stacks called grana)
(an oval with stacks of pancakes inside)
i.
Filled with a green pigment called chlorophyll
d.
Function - Trap the energy from the sun to carry out photosynthesis
5.
Plant and Animal Cells
a. Similarities
i.
Both eukaryotic
ii.
Both have cytoplasm, cell membrane, vacuoles,
ER, ribosomes, Golgi Body, cytoskeleton, mitochondria, nucleus, nucleolus, DNA,
b. Differences
i.
Plant cells have cell wall, plastids like the
chloroplast, and one large vacuole
ii.
Animal cells have centrioles, small vacuoles, no
cell wall
6.
Cell Organization
a. Unicellular
– organism made of only one cell
b. Multicellular
– organism made of more than one cell
c. Cell
differentiation (specialization) – cells in multicellular organisms have
different jobs
d. Tissue
– group of cells that work together to perform a certain function
i.
Human tissues
1. Epithelial
– act as a lining
a. Skin,
stomach lining,
2. Connective
a. Cartilage,
bone, blood
3. Muscular
a. Skeletal
– biceps of the arm
b. Cardiac
– heart
c. Smooth
– organ muscles like the stomach
4. Nervous
– sends and receives electrical impulses
a. Nerves,
spinal cord, brain
ii.
Plant tissues
1. Xylem
– carry water and minerals
2. Phloem
– carry nutrients like sugars
e. Organ
– a group of tissues that work together to carry out a certain function
f.
System – a group of organs that work together
g. Organism
– all of the systems working together
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