B1 Cell structure and transport

active transport

the movement of substances from a dilute solution to a more concentrated solution against a concentration gradient, requiring energy from respiration

algae

simple aquatic organisms (protista) that make their own food by photosynthesis

alveoli

tiny air sacs in the lungs that increase the surface area for gaseous exchange

bacteria

single celled prokaryotic organisms

cell membrane

the membrane around the contents of a cell that controls what moves in and out of the cell

cell wall

the rigid structure around plant and algal cells. It is made of cellulose and strengthens the cell

cellulose

the complex carbohydrate that makes up plant and algal cell walls and gives them strength

Chlorophyll

the green pigment contained in the chloroplasts

chloroplasts

the organelles in which photosynthesis takes place

cytoplasm

the water-based gel in which the organelles of all living cells are suspended and most of the chemical reactions of life take place

Diffusion

the spreading out of the particles of any substance in a solution, or particles in a gas, resulting in a net movement of particles from an area of higher concentration to an area of lower concentration down a concentration gradient

eukaryotic cells

cells from eukaryotes that have a cell membrane, cytoplasm, and genetic material enclosed in a nucleus

hypertonic (osmosis)

a solution that is more concentrated than the cell contents

hypotonic (osmosis)

a solution that is less concentrated than the cell contents

isotonic (osmosis)

a solution that is the same concentration as the cell contents

mitochondria

the site of aerobic cellular respiration in a cell

nucleus

organelle found in many living cells containing the genetic information surrounded by the nuclear membrane

osmosis

the diffusion of water through a partially permeable membrane from a dilute solution (which has a high concentration of water) to a concentrated solution (with a low concentration of water|) down a concentration gradient

partially permeable membrane

a membrane that allows only certain substances to pass through

permanent vacuole

space in the cytoplasm filled with cell sap

phloem

the living transport tissue in plants that carries dissolved food (sugars) around the plant

plasmolysis

the state of plant cells when so much water is lost from the cell by osmosis that the vacuole and cytoplasm shrink and the cell membrane pulls away from the cell wall

prokaryotic cells

from prokaryotic organisms have a cytoplasm surrounded by a cell membrane, and a cell wall that does not contain cellulose. The genetic material is a DNA loop that is free in the cytoplasm and not enclosed by a nucleus. Sometimes there are one or more small rings of DNA called plasmids

resolving power

a measure of the ability to distinguish between two separate points that are very close together

ribosomes

the site of protein synthesis in a cell

sperm

the male sex cells or gametes that carry the genetic material from the male parent

Stomata

openings in the leaves of plants, particularly on the underside and opened and closed by guard cells, allowing gases to enter and leave the leaf

turgor

the pressure inside a plant cell exerted by the cell contents pressing on the cell wall ventilated movement of air or water into and out of the gas exchange organ, for example lungs or gills

xylem

the non-living transport tissue in plants that transports water from the roots to the leaves and shoots