unit 2 apbio quiz

Prokaryotes

Cells that do not have a nucleus; their DNA floats freely in the cytoplasm.

Eukaryotes

Cells that have a nucleus containing their DNA.

Prokaryotic cell size

1-10 µm.

Membrane-bound organelles

Present in eukaryotic cells.

Example of a prokaryote

Bacteria or Archaea.

Example of a eukaryote

Animal, plant, fungi, or protist cell.

Rough Endoplasmic Reticulum (Rough ER)

Makes and modifies proteins for export.

Rough ER appearance

It has ribosomes attached to its surface.

Smooth Endoplasmic Reticulum (Smooth ER)

Synthesizes lipids and detoxifies drugs.

Golgi apparatus

Modifies, sorts, and ships proteins and lipids.

Mitochondria

Produces ATP (energy) through cellular respiration.

Mitochondrion nickname

Called the 'powerhouse' of the cell because it generates the cell's usable energy (ATP).

Lysosomes

Digest wastes, old organelles, and foreign material.

Vacuole in plant cells

Stores water and maintains cell pressure.

Chloroplasts

Performs photosynthesis (makes glucose using sunlight).

Cell/plasma membrane

Controls what enters and leaves the cell; maintains homeostasis.

Cell membrane composition

Phospholipid bilayer.

Ribosomes

Builds proteins from amino acids.

Ribosome locations

Free in cytoplasm or attached to the Rough ER.

Surface area of a cube formula

6 × (side length)².

Volume of a cube formula

(side length)³.

SA:V ratio formula

Surface Area ÷ Volume.

Effect of doubling cell side length on SA:V ratio

It decreases — diffusion becomes less efficient.

Efficiency of small cells

They have a higher SA:V ratio, allowing faster exchange of materials.

Cell size and diffusion rate

Smaller cells diffuse materials faster.

Consequence of a cell growing too large

Diffusion slows down and the cell may divide.

Reason cells stay small

To maintain a high surface area relative to their volume for efficient exchange.

SA:V trend in larger cells

Larger cells are less efficient at diffusion.

Identifying efficient cells for diffusion

The one with the highest SA:V ratio.

Diffusion time in larger vs. smaller cells

Larger cells take longer for molecules to diffuse across.

Organelle definition

Specialized structure within a cell that performs a specific function.

Diffusion definition

Movement of molecules from high to low concentration.

Selective permeability definition

Property of the cell membrane that allows only certain substances to pass through.

Homeostasis definition

Maintaining stable internal conditions in the cell or body.