Unit 3: Cell Biology

Cell Membrane

A thin semi-permeable “skin” that surrounds a cell.

Hydrophilic

Attracted to water; specifically the polar head of a phospholipid.

Hydrophobic

Repels water; specifically the nonpolar tail of a phospholipid.

Passive Transport

Does not require energy ($ATP$) to move molecules; includes Diffusion, Facilitated Diffusion, and Osmosis.

Active Transport

Requires energy ($ATP$) to move molecules; pumps molecules from low to high concentration using protein channels.

Solvent

The dissolving medium (usually water).

Solute

A substance being dissolved.

Diffusion

Movement of molecules from high concentration to low concentration.

Osmosis

Diffusion of water across a selectively permeable membrane toward the area with more solute (lower water concentration).

Isotonic Solution

An equal concentration of particles inside and out where the net movement of water is zero and the cell stays the same size.

Hypertonic Solution

More particles in the solution than in the cell causing water to move out to try to dilute the surroundings and the cell to shrivel.

Hypotonic Solution

Fewer particles in the solution than in the cell causing water to move in to try to dilute the internal environment and the cell to expand.

Endocytosis

Bringing molecules into the cell by forming vesicles.

Exocytosis

Secreting molecules out of the cell by releasing a vesicle.

Cell Membrane Components

Includes a phospholipid bilayer (hydrophilic heads on the surface and hydrophobic tails in the middle), cholesterol, receptor proteins, pore proteins, and channel proteins.

Cholesterol

Helps maintain membrane flexibility and stability.

Veins

Blood vessels that bring blood back to the heart.

Capillaries

Small blood vessels on the alveoli.

Hemoglobin

Protein in red blood cells that carries oxygen.

Reactant

What goes into a chemical reaction.

Product

What comes out of a chemical reaction.

Photosynthesis Formula

$$\text{Carbon Dioxide} + \text{Water} + \text{Light} \rightarrow \text{Sugar} + \text{Oxygen}$$

Cellular Respiration Formula

$$\text{Glucose} + \text{Oxygen} \rightarrow \text{Water} + \text{Carbon Dioxide} + \text{ATP (Energy)}$$

Cellular Respiration Steps

1. Glycolysis, 2. Krebs Cycle, 3. Electron Transport Chain.

Homeostasis

The maintenance of relatively stable internal conditions despite external conditions.

Vena Cava

Where blood enters the heart.

Pulmonary Artery

Where blood is carried to the lungs.

Aorta

Where blood is carried to the body.

Lactic Acid Fermentation

A type of anaerobic respiration occurring in animals and bacteria.

Alcoholic Fermentation

A type of anaerobic respiration occurring in fungi and bacteria.

Aerobic Respiration

Requires oxygen, happens in the mitochondria, and is common in eukaryotic cells.

Anaerobic Respiration

Happens when there is no oxygen and/or in cells without mitochondria; also known as Fermentation.

Alveoli

Where gas exchange happens in the lungs.

Arteries

Blood vessels that take blood away from the heart.

Concentration Gradient

A difference in the concentration of molecules between two areas. Molecules naturally move from high concentration to low concentration.

Facilitated Diffuc

Passive transport that uses a protein channel to move molecules from high concentration to low concentration.

Glycolysis

The first step of cellular respiration. Occurs in the cytoplasm and breaks down glucose.

Electron Transport Chain (ETC)

The final stage of cellular respiration. Produces the most ATP and requires oxygen as the final electron acceptor.

NADH & FADH₂

Electron carriers that transport high-energy electrons to the electron transport chain.

Blood Flow Through the Heart

• 1: Vena cava (Superior & Inferior)

• 2: Right atrium

• 3: Right ventricle

• 4: Pulmonary artery

• 5: Lungs (labeled as "to lungs")

• 6: Pulmonary veins (labeled as "from lungs")

• 7: Left atrium

• 8: Left ventricle

• 9: Aorta

• 10: Out to body

Capillaries

Small blood vessels on the alveoli.

Bone Marrow produces…

Produces red blood cells that carry oxygen.

Sternum

Breastbone that protects the heart.