Download Cells and Cell Processes

All You Need to Know About Cells
1. Know the following organelles and their functions:
Nucleus ............................ Control center (contains DNA and the nucleolus).
Vacuoles........................... Storage compartments for waste, food, and water.
Plants have one large one. Animals have several smaller ones (called ‘vesicles’)
Plasma Membrane .......... The cell membrane. Provides support and protection and is semi-permeable.
Mitochondria .................. The energy generator of the cell. Converts energy stored in O2 and C6H12O6 into ATP.
Ribosomes........................ Make proteins by joining amino acids. This is the site of translation in protein synthesis.
Endoplasmic reticulum . Transport system of the cell.
Golgi Apparatus ............. Packages and distributes proteins.
Centriole .......................... ONLY IN ANIMALS. This structure aids in cell division.
Chloroplasts .................... ONLY IN PLANTS. This is the site of photosynthesis.
Cell Wall .......................... ONLY IN PLANTS (and bacteria, fungus, and algae).
The cell wall surrounds the cell membrane and gives
support and protection to the cell. In plants, it’s made of
cellulose.
2. Know the Cell Theory:
1. All living things are made of cells.
2. Cells are the basic unit of structure and function in living things.
3. All cells come from preexisting cells.
3. Know the difference between prokaryotic and eukaryotic cells
Prokaryotic Cells
Eukaryotic Cells
Have a nucleus
Do not have a nucleus
Have linear chromosomes
Have circular chromosomes (plasmids)
Have many membrane-bound organelles*
Do not have membrane-bound organelles*
Size: larger
Size: very small
Includes plants, animals, fungus, protists
Only includes bacteria
*Membrane-bound organelles refer to membrane-bound structures within the cell that carry out a particular
function such as mitochondria, chloroplasts, nucleus, etc.
4. Know your stem cells:
All cells in an organism have the same DNA, more or less. Specialized cells behave differently based on
which sections of their DNA instructions are turned on. Stem cells have the power to turn into any type of cell in
the body because they haven’t begun the process of differentiation into specialized cells yet.
5. Know how to get essential materials, such as water or food, in and out of cells.
□Passive transport requires no energy from the cell.
Some things can just diffuse in, - they go from high to low concentrations without any effort (energy) from the cell.
Oxygen (O2) diffuses into cells. Carbon Dioxide (CO2) diffuses out.
When the substance diffusing is water, this process is called osmosis.
What happens to a cell in salt water? - Water leaves the cell and… it shrivels and dies.
What happens to a cell in fresh water? - Water enters the cell and … it expands and may explode.
□Active transport requires energy (ATP) from the cell.
*When materials are too large to fit through the cell membrane, the cell must use energy.
‘Endocytosis’
Using energy to get large materials into the cell
‘Exocytosis’
Using energy to get large materials out of the cell.
*When materials move against the concentration gradient (from low to high), the cell must use energy to run pumps.
** Diffusion works well only in very small or very thin cells. When cells grow too large, diffusion becomes a
serious problem: Diffusion is just too slow to keep up with the increased space within an enormous cell. It can’t
get enough materials across the membrane to supply the inside of the cell: (the surface/volume ratio decreases
rapidly as the cell increases in size). When cells get too big, they divide to form two smaller cells…
□A Semi-permeable membrane, such as the cell membrane is selective about what materials are allowed to pass.
Some substances can get through, others cannot. Cells restrict the entry of molecules based on SIZE and CHARGE.
SIZE:
Only the smallest molecules can get through (even H2O has a lot of trouble getting in)
CHARGE:
The lipids in the cell membrane are nonpolar, repelling all charged (+) or (-) molecules.
Non-polar (neutral) molecules can get through very easily
(even very large non-polar molecules like testosterone or estrogen can get right through)
Label 10 components of a plant cell:
Match 10 components of a plant cell with their functions:
Organelle
Function
Nucleus
Control center (contains DNA)
Cell Wall
Converts the energy stored in glucose into ATP (respiration)
Chloroplast
Liquid inside cell, contains enzymes and raw materials
Cytoplasm
Make proteins by joining amino acids together.
Endoplasmic Reticulum
Packages and distributes proteins.
Golgi Apparatus
Provides structure for plant cells, made of cellulose
Mitochondria
Semi-permeable barrier around all cells.
Plasma Membrane
Site of photosynthesis
Ribosome
Storage compartment for waste, food, and water
Vacuole
Transport system of the cell.
Answer the following questions about cellular transport:
Many marine invertebrates have body surfaces that are permeable
to water but not to salt. Osmosis can change the pressure of their
body fluids. Fortunately, the ocean is very stable in its salt content.
What would happen if a jellyfish were placed in a very low-salt
environment such as an estuary?
 It would gain water from the environment.
 It would gain nutrients from the water in the environment.
 It would lose proteins into the water.
 It would lose salt into the water
A student was studying the responses of cells
to solutions of varying salt concentrations.
Which solution below would cause no
change in cell size?




The diagram shows a section of a cell membrane
that includes a channel protein. The function of
this protein is to —
 strengthen the outer boundary of the cell
 connect reproductive cells during fertilization
 allow certain substances to enter or leave the cell
 exchange organelles or chromosomes between specialized cells
This diagram shows molecules represented by ‘X’
both outside and inside of a cell. A process that
would result in the movement of these molecules
out of the cell requires the use of  DNA  ATP
 antigens  antibodies
Living organisms must be able to obtain materials, change the
materials into new forms, remove poisons, and move needed
material from one place to another. Many of these activities directly
require –
 energy released from ATP
 carbohydrates formed from receptor molecules
 the synthesis of DNA
 the breakdown of energy-rich inorganic molecules