Cell (Plasma) Membrane:
○ A thin, two-layered film that surrounds the entire cell.
○ Made up of proteins and lipids
○ It is described as semi-permeable (selectively permeable): permits the passage or transport of
certain materials into and out of the cell and prevents the transport of other materials.
○ It keeps the internal conditions of the cell constant to help maintain homeostasis.
Cytoplasm:
○ Fluid-like material inside the plasma membrane and outside the nucleus of the cell
○ Many of the substances in cell metabolism are dissolved here.
Nucleus:
○ A large, dense membrane-enclosed body that controls the cell's metabolism and reproduction.
Nuclear Membrane (Envelope):
○ Selectively permeable double structure that surrounds the nucleus.
○ The pores control the passage of substances into and out of the nucleus.
○ The nucleoplasm remains chemically different from the rest of the cell.
Nucleolus:
○ Structure within the nucleus that is involved in the synthesis of the RNA found in the ribosomes.
○ Site of the production of ribosomes.
○ It disappears at the beginning of cell division and reappears at the end.
Endoplasmic Reticulum:
○ A network of channels in the cytoplasm that function in synthesizing,
transporting, and storing substances made in the cell.
○ Provide a large surface area on which many biochemical reactions may
occur.
Ribosomes:
○ Small structures that are the sites of protein synthesis.
○ Found in the cytoplasm and lining the membranes of the ER.
Mitochondria:
○ Round, slipper-shaped organelle that release the energy in food
molecules for use by the cell.
○ Site of Aerobic Cellular Respiration.
○ Powerhouse of the cell; ATP (energy) is made here.
Golgi Complex(Body/Apparatus):
○ Membrane-bound channels in which materials are synthesized or packaged.
Lysosome:
○ Small sac-like structures that contain digestive enzymes and which take part in the digestion of food
materials.
○ They break down worn-out cell organelles, kill bacteria, part of the body's defense against disease.
Vacuoles:
○ Spaces in the cytoplasm enclosed by a membrane storing water, food, wastes and other materials.
○ Turgor Pressure
Centrioles:
○ Cylindrical structures found outside the nuclear membrane in most animal cells
○ Involved in cell division
Cell Wall:
○ Non-living structure made up of cellulose found only in plant cells.
Gives the cell its shape and provides protection for the cell.
○
Chloroplasts (Plastid):
○ Found in plant cells and some protists that contain the pigment chlorophyll and are the sites of
photosynthesis.
Microtubules:
○ Long, hollow, cylindrical structures found in the cytoplasm that serves as a sort of skeleton for the cell
giving it shape.
○ Involved in movement of the chromosomes during cell division.
Microfilaments:
○ Long, solid, thread-like strands found in some cells that are associated with cell movement
Cilia:
○ Tiny beating hairs for locomotion
○ Ex. Paramecium, Cilia
Flagella:
○ Long, whip-like tail involved in locomotion
○ Ex. A sperm cell
Parts of Cilia and Flagella:
Cells
Cells have 3 main jobs
● make energy
○ need energy for all activities
○ need to clean up waste produced while making energy
● make proteins
○ proteins do all the work in a cell, so we need lots of them
●
make more cells for growth
○ to replace damaged or diseased cells
Organelles (Eukaryotic cells)
Cell Membrane
Function
- separates cell from outside
- controls what enters or leaves cell
- O2, CO2, food, H2O, nutrients,
waste
- recognizes signals from other cells
- allows communication between cells
Structure
- double layer of fat
- phospholipid bilayer
- receptor molecules
- proteins
Vacuoles and Vesicles
Function
- moving material around the cell (vesicles)
- storage for Oxygen, H2o, etc. (vacuoles)
- larger in plant cells because plant
cells do not move
Structure
- membrane sac
Lysosomes
Function
- digest food
- used to make energy
- clean up & recycle
- digest broken organelles
Structure
- membrane sac of digestive enzymes
Mitochondria
Function
- make ATP energy from cellular respiration
- sugar + O2 → ATP
- fuels the work of life
Structure
- double membrane
- has its own DNA
Chloroplasts
- make energy + sugar from sunlight
- photosynthesis
- sunlight + CO2 → ATP & sugar
- ATP = active energy
- sugar = stored energy
-
-
build leaves &
roots & fruit out
of the sugars
found only in plant cells
Nucleus
Function
- control center of cell
- protects DNA
- instructions for building proteins
Structure
- nuclear membrane
- nucleolus
- ribosome factory
- chromosomes
- DNA
Ribosomes
Function
- protein factories
- read instructions to build proteins from
DNA
Structure
- some free in cytoplasm
- some attached to rough ER
ER (endoplasmic reticulum)
Function
- works on proteins
- helps complete the proteins after ribosome
builds them
- makes membranes
Structure
- rough ER
- ribosomes attached
- works on proteins
- smooth ER
- makes membranes
Golgi Apparatus
Function
- finishes, sorts, labels & ships proteins
- like UPS headquarters
- shipping & receiving
department
- ships proteins in vesicles
- “UPS trucks”
Structure
- membrane sacs
-
only in animal cells
- cell plates in plant cells
Structure
- one pair in each cell
Centrioles
Function
- help coordinate cell division
Animal Cell Organelles
Cell membrane: Border of the cell, allows things in
Centrioles: Cell division
and out by size
Lysosomes: For food digestion, garbage disposal and
Nucleus: protects DNA, holds chromosomes and
recycling.
nucleolus
Golgi Apparatus: Finishes, packages and ships
Nucleolus: Ribosome factory
proteins
Chromosomes: Shrinked versions of DNA
Mitochondria: Produces ATP
Rough ER: Connected to nucleus, holds ribosomes
Vacuoles: Storage for Oxygen, H2o, etc
which make proteins
Vesicles: Transports proteins both inside and outside
Ribosomes: Make proteins
the cell
Smooth ER: Stores and creates lipids and steroids
Cytoplasm: Holds organelles in place
Plant Cell Organelles
Cell membrane: Border of the cell, allows things in
Lysosomes: For food digestion, garbage disposal and
and out by size
recycling.
Nucleus: protects DNA, holds chromosomes and
Golgi Apparatus: Finishes, packages and ships
Nucleolus
proteins
Nucleolus: Makes ribosomes
Mitochondria: Produces ATP
Chromosomes: Shrinked versions of DNA
Vacuoles: Storage for Oxygen, H2o, etc
Rough ER: Connected to Nucleus, holds ribosomes
Vesicles: Transports proteins both inside and outside
which makes proteins
the cell
Ribosomes: Makes proteins
Cell Wall: Provides structure and protection for the
Smooth ER:
cell
Cell Plate: Cell division
Cytoplasm: Holds organelles in place
Enzymes
-
A protein catalyst
-
Enzymes are important proteins found in living things. An enzyme is a protein that changes the
rate of a chemical reaction.
-
They speed metabolic reactions.
Chemical Reactions of Life
●
●
Processes of life
building molecules
○ synthesis
● breaking down molecules
○ digestion
All chemical reactions in living organisms require enzymes to work
-
building molecules
- synthesis enzymes
breaking down molecules
Each enzyme is the specific helper to a specific reaction
-
each enzyme needs to be the right shape for the job
-
enzymes are named for the reaction they help
-
sucrase breaks down sucrose
-
proteases breakdown proteins
-
lipases breakdown lipids
-
DNA polymerase builds DNA
-
end in -ase
Enzymes aren’t used up
-
Enzymes are not changed by the reaction
-
used only temporarily
-
re-used again for the same reaction with
other molecules
-
very little enzyme needed to help in many
reactions
Lock & Key model
-
shape of protein allows enzyme & substrate to fit
-
specific enzyme for each specific reaction
Enzyme vocabulary
-
Enzyme- helper protein molecule
-
Substrate- molecule that enzymes work on
-
Products- what the enzyme helps produce from the
reaction
-
- digestive enzymes
enzymes speed up reactions
- “catalysts
-
Active site- part of enzyme that substrate molecule fits into
What affects enzyme action?
-
Correct protein structure
-
-
correct order of amino acids
Temperature
-
Effect on rates of enzyme activity
-
Optimum temperature
-
greatest number of collisions between enzyme & substrate
-
human enzymes
-
-
Raise temperature (boiling)
-
-
-
35°- 40°C (body temp = 37°C)
denature protein = unfold = lose shape
Lower temperature T°
-
molecules move slower
-
fewer collisions between enzyme & substrate
pH (acids & bases)
-
Effect on rates of enzyme activity
-
changes in pH changes protein shape~ Denatures
-
most human enzymes = pH 6-8
-
depends on where in body
-
pepsin (stomach) = pH 3
-
trypsin (small intestines) = pH 8
Why? enzyme has to be right shape
-
order of amino acids
-
wrong order = wrong shape = can’t do its job
-
amino acids are the blocks to make proteins