Unit 4: Cell Transport and Cell Energy

Hydrophobic

repelled by water; does not mix or dissolve in water

Semipermeable (selectively permeable)

allows some substances to pass through while blocking others

Passive transport

movement of molecules across a membrane without using energy

Diffusion

movement of particles from an area of high concentration to low concentration

Osmosis

diffusion of water across a semipermeable membrane

Concentration gradient

the difference in the concentration of a substance across a space or membrane

Hypertonic solution

a solution with a higher solute concentration compared to another solution

Hypotonic solution

a solution with a lower solute concentration compared to another solution

Isotonic solution

a solution with equal solute concentration compared to another solution

Facilitated diffusion

passive transport of molecules through membrane proteins

Active transport

movement of molecules across a membrane using energy (ATP)

ATP

the main energy-carrying molecule of the cell

Cellular respiration

process cells use to break down glucose and produce ATP

Product

a substance formed as the result of a chemical reaction

Reactant

a starting substance in a chemical reaction

Mitochondria

organelles where cellular respiration occurs

Glucose

a simple sugar that is a major energy source for cells

Glycolysis

the first stage of cellular respiration that breaks glucose into pyruvate

Electron carrier

a molecule that transports electrons during cellular respiration or photosynthesis

Krebs Cycle

the second stage of cellular respiration that releases energy and CO₂

Electron Transport Chain (ETC)

a series of proteins that use electrons to create ATP

ATP synthase

an enzyme that makes ATP using energy from a hydrogen ion gradient

Fermentation

an anaerobic process that makes ATP without oxygen

Lactic Acid fermentation

fermentation in which glucose is converted into lactic acid

Alcohol fermentation

fermentation in which glucose is converted into alcohol and CO₂

Photosynthesis

process plants use to convert light energy into chemical energy (glucose)

Chloroplasts

organelles in plant cells where photosynthesis occurs

Chlorophyll

the green pigment that absorbs light energy for photosynthesis

Thylakoid

membrane sacs inside chloroplasts where light-dependent reactions occur

Light-dependent reaction

the part of photosynthesis that requires light to make ATP and NADPH

Light-independent reaction

the part of photosynthesis that uses ATP/NADPH to make glucose

Stroma

the fluid-filled space in chloroplasts where the Calvin Cycle occurs

Calvin Cycle

the cycle that converts CO₂ into glucose during photosynthesis

Pigment

a molecule that absorbs certain wavelengths of light

Autotrophs

organisms that make their own food (like plants)

Heterotrophs (Consumers)

organisms that cannot make their own food and must consume others