Standard 2.1
Relate cell parts/organelles (plasma membrane, nuclear envelope, nucleus, nucleolus, cytoplasm, mitochondrion, endoplasmic reticulum, Golgi apparatus, lysosome, ribosome, vacuole, cell wall, chloroplast, cytoskeleton, centriole, cilium, flagellum, pseudopod) to their functions. Explain the role of cell membranes as a highly selective barrier (diffusion, osmosis, facilitated diffusion, active transport).
Vocabulary
Tier 3
membrane - surrounds the cell
phospholipid bilayer - two layered membrane
semipermeable - the membrane allows some molecules to pass in
hydrophilic head - part of membrane that faces out, towards the water
hydrophobic tail - part of the membrane that faces in, away from the water
concentration gradient - when there are more molecules on one side of a membrane than the other. If there is a concentration gradient molecules will want to even out the sides
osmosis - movement of water across a semipermeable membrane
diffusion - natural movement of molecules
facilitated diffusion - the movement of molecules using a membrane protein
equilibrium - same number of molecules on each side of the membrane
hypertonic - water moves out of the cell
isotonic - no net water movement
hypotonic - water moves into the cell
passive transport - molecules move across the membrane for no energy
active transport -molecules require ATP energy to move across the membrane
ATP - energy molecule
Organelles - tiny, little structures inside the cells
nucleus - center of the cell that holds the DNA
golgi body - organelle that packages and ships protein
endoplasmic reticulum - network of sacs around the nucleus that aid in moving protein
ribosomes - factories that make protein
mitochondria - organelle where you make energy via cellular respiration
cytoplasm - jelly of the cell
cytoskeleton - protein fibers in the cytoplasm that give the cell some firmness
centrioles - form the mitotic spindle during mitosis and meiosis
chloroplast/plastid - plant organelle where photosynthesis happens
vacuole - plant organelle where water is stored
cell wall - plant organelle which lets the plant cell swell up with water without bursting
The Cell Membrane:
The cell membrane is the barrier around ALL cells on the planet, eukaryotic and prokaryotic. Not viruses, since they are not even cells.
It is made of a PHOSPHOLIPID BILAYER:
* The bilayer "heads" love water and the "tails" hate water so they are on the inside
It is made of a PHOSPHOLIPID BILAYER:
* The bilayer "heads" love water and the "tails" hate water so they are on the inside
* This membrane bilayer is said to be SEMIPERMEABLE which means it allows some molecules to pass into the cell while keeping out most other molecules.
Concentration gradient: When molecules move from one side of a membrane to the other because there are more molecules on one side than the other.
Which direction will the purple molecules move? To the right, until they are even.
How do molecules move into and out of the cell?
Passive transport: When molecules move across a membrane WITHOUT using energy. It's Free!!
There are 3 types of passive transport into and out of cells...
1. Diffusion: Diffusion is when molecules just move automatically until they are evenly spread out
2. Osmosis: Osmosis is the movement of water molecules across a membrane
Cells can be in one of three osmotic states:
isotonic = no osmosis
hypotonic = osmosis moves water INTO the cell, fattening it up or popping it
hypertonic = osmosis moves water OUT of the cell, killing it
3. Facilitated diffusion: diffusion through a membrane protein
Osmosis in Cells:
In a hypotonic (big like a hippo) solution animal cells burst, but plant cells like it, that's why they have a cell wall
In an isotonic solution it is just right for an animal cell, but plants don't like this too much and they wilt
In a hypertonic solution, all cellsdie because they shrink and dehydrate
--> Salt causes cells to become hypertonic, that is why we salt meat and fish, so bacteria and fungus die. It's also why we have kidneys and urinate, to flush out the salt so our cells don't get hypertonic and dehydrate and die.
Active Transport: When ENERGY is used to move molecules AGAINST their concentration gradient
Here in the diagram, H ions are pushed out of the cell in the opposite direction using ATP as the energy source.
THE ORGANELLES
Chloroplast/Plastid
Organelles that perform photosynthesis
Light + CO2 +H2O --> O2 + C6H12O6
Light reacts with carbon dioxide and water to form sugar and oxygen
Light + CO2 +H2O --> O2 + C6H12O6
Light reacts with carbon dioxide and water to form sugar and oxygen
Centrioles
Help during cell division by creating the mitotic spindle
Cytoplasm and Cytoskeleton
The cytoplasm is the clear, "jelly" fluid in the cell
The cytoskeleton are protein fibers that run through out the cell to keep its shape and help transport molecules
Endoplasmic Reticulum (ER)
* The ER is wrapped around the nucleus.
*It is a warehouse for protein production
If it has ribosomes on it, it is called the rough ER, if not, smooth ER
Ribosomes
MAKE PROTEIN
They are very small "dots" even under a microscope
They are very small "dots" even under a microscope
Golgi Body
*Packages and ships proteins
*Vesicles break off and add on to the Golgi
*Vesicles break off and add on to the Golgi
Lysosomes
Lysosomes are vesicles that break off of the Golgi
They contain digestive enzymes which destroy bacteria or old organelles
They are like the GARBAGE COLLECTORS
PLANT ORGANELLES
Vacuole
Large sacs of water in a plant cell
Cell Wall
*Made of the "crunchy" carbohydrate cellulose
*Helps keep the shape of the plant cell in a hypotonic evironment
Nucleus
Part of the cell that contains the genetic material DNA
The nucleolus is in the nucleus. It is a small organelle that makes ribosomes
The nucleus has holes in it, or pores, so mRNA can leave
The nucleolus is in the nucleus. It is a small organelle that makes ribosomes
The nucleus has holes in it, or pores, so mRNA can leave
Mitochondria
Standards 2.4 Identify the reactants, products, and basic purposes of photosynthesis and cellular respiration. Explain the interrelated nature of photosynthesis and cellular respiration in the cells of photosynthetic organisms.
2.5 Explain the important role that ATP serves in metabolism.
Makes energy by Cellular Respiration
SUGAR + OXYGEN --> WATER + CARBON DIOXIDE + ATP
C6H12O6 + O2 --> H2O +CO2 + ATP
ATP is the energy molecule in the cell
* The mitochondria has its own DNA. It is theorized that they used to be bacteria, but are now part of the eukaryotic cell!
* NO prokaryotic cells have mitochondria
2.5 Explain the important role that ATP serves in metabolism.
Makes energy by Cellular Respiration
SUGAR + OXYGEN --> WATER + CARBON DIOXIDE + ATP
C6H12O6 + O2 --> H2O +CO2 + ATP
ATP is the energy molecule in the cell
* The mitochondria has its own DNA. It is theorized that they used to be bacteria, but are now part of the eukaryotic cell!
* NO prokaryotic cells have mitochondria