bio quiz 4

Vocabulary flashcards covering plant pigments, chloroplast structures, light-dependent reactions, photosystems, redox processes, and the Calvin cycle based on lecture notes.

Accessory pigments

Helper molecules that absorb extra light colors that chlorophyll misses.

Absorption spectrum

A graph showing which colors of light a pigment absorbs best.

Stoma

A tiny pore on a leaf that lets gases in and out.

Guard cells

Cells that open and close a leaf pore.

Mesophyll cells

Cells inside a leaf where most photosynthesis happens.

Stroma

The fluid filling inside a chloroplast surrounding the thylakoids.

Granum

A stack of green thylakoid discs inside a chloroplast.

Thylakoid

A single green disc inside a chloroplast where light reactions happen.

Photosystem

A protein and pigment group that collects light energy.

Reaction center

The middle area of a photosystem where light energizes electrons.

Antenna pigments

Outer pigments that gather light energy and pass it to the center.

Light-dependent reactions

The first stage of photosynthesis that uses sunlight and $H_2O$ to make ATP, NADPH, and $O_2$.

Calvin cycle

The second stage of photosynthesis that uses stored energy and $CO_2$ to make sugar.

Redox reactions

Paired chemical reactions where one molecule loses an electron and another gains it.

Oxidation

The loss of an electron from a molecule.

Reduction

The gain of an electron by a molecule.

Electron transport chain

A line of proteins that passes electrons along to release energy.

Photosystem II

The first light reaction step that splits water and helps make ATP.

Photosystem I

The second light reaction step that re-energizes electrons to make NADPH.

ATP synthase

A protein motor that builds ATP as hydrogen ions flow through it.

Carbon fixation

The process of trapping atmospheric $CO_2$ gas inside an organic molecule.

RuBisCO

The enzyme that attaches $CO_2$ gas to RuBP to start making sugar.

RuBP

The 5-carbon molecule that joins with $CO_2$ during carbon fixation.

GA3P

A 3-carbon sugar piece; joining two of them forms one glucose molecule.

Plasma membrane

The outer shell of a cell that lets things in and out.

Selectively permeable

Letting some things pass through while stopping others.

Aquaporins

Protein channels that let water pass through the membrane quickly.

Solute

Dissolved stuff in a liquid, like salt or sugar.

Diffusion

Molecules moving from a crowded area to a less crowded area.

Osmosis

Water moving across a membrane to where there is less water.

Hypotonic solution

A liquid with less solute that makes a cell swell.

Hypertonic solution

A liquid with more solute that makes a cell shrink.

Isotonic solution

A liquid with the same solute level that keeps a cell the same size.

Dialysis membrane

A barrier with tiny holes that lets small water molecules pass through while blocking larger sugar molecules.

Independent variable

The condition set and changed by the researcher, plotted on the x-axis of a graph.

Dependent variable

The outcome measured during an experiment, plotted on the y-axis of a graph.

Bag in lower outside sugar

Water flows into the bag, causing it to gain weight.

Bag in higher outside sugar

Water flows out of the bag, causing it to lose weight.

Solute concentration gradient

The difference in sugar concentration between the inside and outside of a bag, which determines how much weight is gained or lost.

Cell wall

A rigid outer structure around a plant cell membrane that gives support.

Preferred environment for plant cells

A hypotonic environment, which allows water to flow into the cells.

Turgor pressure

The push of water inside a plant cell against its rigid cell wall.

Turgid

The state of a plant cell being swollen and firm from taking in water.

Why plant cells do not burst in water

The rigid cell wall limits swelling and prevents the cell from bursting.

Percent weight change formula

$$\text{\% Weight Change} = \frac{\text{Final Weight} - \text{Initial Weight}}{\text{Initial Weight}} \times 100$$

X-axis of an osmosis graph

Shows the amount of sugar in the liquid outside the potato.

Y-axis of an osmosis graph

Shows how much weight the potato gained or lost.

Zero weight change on the graph

The exact sugar level where water does not enter or leave the potato, so weight stays the same.

Hypotonic liquid (low sugar outside)

Water flows inside the potato, making it gain weight.

Hypertonic liquid (high sugar outside)

Water flows out of the potato, making it lose weight.

Effect of big sugar differences

A bigger difference in sugar concentration makes water move faster into or out of the cell.

X-axis of the osmosis graph

Shows the amount of sugar in the liquid outside the potato.

Y-axis of the osmosis graph

Shows how much weight the potato gains or loses.

Isotonic point on the graph

The exact sugar level where weight change is $0\%$, so the potato stays the same weight.

Hypotonic liquid (low sugar outside)

Liquid with less sugar than the potato, so water flows inside and the potato gains weight.

Hypertonic liquid (high sugar outside)

Liquid with more sugar than the potato, so water flows out and the potato loses weight.

How sugar concentration affects water speed

A bigger difference in sugar concentration makes water move into or out of the cell much faster.

Semi-permeable

Allows tiny molecules like water to pass through, but stops bigger ones.

Differentially permeable

Selects which specific molecules can pass through and which cannot.

Impermeable

Blocks everything from passing through.