CELL Parts and CELL Membrane REVIEW

Name the cell part that corresponds to the function

Control Center (Brain of the Cell) The Nucleus

Makes Ribosomes and is found inside the Nucleus The Nucleolus

Where proteins are made? On the Ribosomes

Packages, stores, and distributes proteins; pancake-shaped layers Golgi Apparatus

Thick fluid inside cells CYTOPLASM

Hair-like extensions that help cells sense their surroundings Cilia

Has a double membrane called the “nuclear envelope” The Nucleus

Folded membrane that transports proteins throughout the cell The Endoplasmic Reticulum

Contains chlorophyll, found only in plant cells Chloroplast

The “powerhouse” of the cell, site where ATP is made Mitochondria

Boundary of the cell, found in both plant and animal cells The cell membrane

Digests (breaks down) wastes and old cell parts, kills bacteria and viruses Lysosome

Tail-like extension that helps move some cells through watery environments Flagella

Stores water, wastes, and nutrients for plants Central Vacuole

Rigid outside boundary for plant cells Cell Wall

Now let’s examine the Membrane! What does selective permeability mean? Selective= choosy, picky, doesn’t let just anything in. Permeable= allow substances to enter and exit. Selective permeability= the ability of the membrane to let some things in and keep others out.

The membrane is made of these! Phospholipid Molecules They have the following parts: Phosphate and Glycerol Head (polar) Fatty Acid Tails (nonpolar)

Why is the membrane so fluid? Fatty acid tails are unsaturated (kinked) so they don’t compress Cholesterol is embedded (stuck in) between the tails

What other components make the membrane a mozaic? transport proteins What are three examples of transport proteins? 1. gated proteins 2. channel proteins 3. receptor proteins

Why are transport proteins needed? They allow substances that are too… Big, charged or polar to cross the membrane.

What substances can or cannot pass easily across the membrane? CANCANNOT  Polarity NonpolarPolar  Size SmallLarge  Charge UnchargedCharged

What is a concentration gradient? Different concentrations of molecules between two areas. If there is no difference, there is no gradient— You have equilibrium!

When is there equilibrium? When there is an equal concentration of molecules on both sides of a membrane or throughout the space. Why is it called “Dynamic” Equilibrium? The molecules are always moving (dynamic), but the concentration stays equal.

Movement of molecules from high concentration to low concentration Diffusion

Diffusion of Water Molecules Osmosis

Two types of Transport: Active Transport Passive Transport

Name kinds of Passive Transport- Remember-- no additional energy required Diffusion Osmosis Facilitated Diffusion=movement down a gradient for substances that cannot easily cross the membrane– they need to be helped or assisted by a ……. Transport protein

Name two kinds of Active Transport– these require energy input Endocytosis– Endo= IN Exocytosis- Exo = Exit

Solutions: Hypertonic Hypotonic Isotonic Which has more dissolved solutes? Hyper Which has more H2O? Hypo

Water always moves from …… Hypo to Hyper Hypotonic solutions-- (mo H2O) To Hypertonic solutions-- more solutes, but less H2O

Thank you and Good-Luck!

Plant cells need water to maintain upright structure. What is this pressure called? Turgor Pressure When a plant loses turgor pressure, it loses water from osmosis. That’s called…… Plasmolysis