Nat 5 Biology - Cell Biology

Plasmolysed

When plant cells lose water, the contents shrink away from the cell wall, but the cell is still alive

Turgid

When pure water plant cells gain water, the cell wall prevents it from bursting

Osmosis

Movement of water molecules from an area of high water concentration to an area of low water concentration through a selectively permeable membrane

Diffusion

Movement of molecules down a concentration gradient from an area of high concentration to an area of low concentration

Passive Transport

Movement of substances down a concentration gradient, does not require any energy

Concentration Gradient

The difference between an area of high concentration and an area of low concentration

Active Transport

Movement of molecules from an area of low concentration to an area of high concentration

Selectively Permeable Membrane

Only allows some substances to pass through, controls substances that enter and exit the cell

Haploid

One set of chromosomes

Chromosomes

Thread like structures within the nucleus of the cell

Diploid

Two sets of chromosomes

Cell Division

Produces new cells by splitting into two daughter cells, essential for growth and repair

Chromosome Complement

Characteristic number of chromosomes in an organism

Aseptic Technique

Used when producing cells in a laboratory to prevent contamination with unwanted micro-organisms

Equator

Centre of the cell

Spindle Fibres

Small fibres which attach themselves to chromosomes during mitosis

Chromatid

When a chromosome makes an identical copy of itself

Mitosis

Important stage during cell division

Nucleus

Contains chromosomes which carry genetic information, controls the cells activities

Cell Wall

Maintains the cells shape, made of cellulose in plants.

Vacuole

Contains cell sap

Ribosomes

Site of protein synthesis

Cellulose

In plant cells surrounding cell membrane, it is rigid

Plasmids

Small circles of DNA in bacterial cells

Chloropast

Site of photosynthesis, contains chlorophyll

Mitochrondrion

Site of aerobic respiration, cells that need a lot of energy have many mitochrondria

Cell Membrane

Made of phospholipids and proteins. Controls the movement of substances in and out the cell

Cytoplasm

The site of chemical reactions in the cell

Amino Acids

Form in chains to make proteins

Structural Protiens

Form the building blocks that make up much of the cell

Hormones

Chemical messengers which control the bodies systems

Enzymes

Catalyst which speeds up chemical reactions

Receptors

Found on the surface of the cell membrane and receive signals from molecules outside the cell

Antibodies

Produced by white blood cells and help prevent the body from having bacteria and viruses

T

Thymine

G

Guanine

C

Cytosine

A

Adenine

Complementary Base Pairing

Bases that fit together in a specific way A-T and C-G

Double Stranded Helix

When strands are twisted together, it is the shape of DNA

DNA

Carries genetic information for making proteins, they make up chromosomes

Genetic Code

Information stored in order of bases in a gene

Messenger RNA

A molecule which carries a complementary copy of the DNA code from the nucleus to the cytoplasm