Cells leaving cert biology

Cell

Smallest unit of living organisms, the building blocks of all life

Unicellular

Living organisms consisting of 1 cell eg bacteria

Multicellular

Living organisms consisting of lots of cells eg humans

Eukaryotic

Cell that contains a nucleus and membrane bound organelles eg plants

Prokaryotic

Cells that dont contain a nucleus or membrane bound organelles eg bacteria

Organelle

Structures within cells that carry out a particular function

Cell membrane

Made of 2 layers of phospholipids with proteins embedded in this bilayer

Semi-permeable which means it only allows some small molecules like water to pass through it

Selectively permeable which means it contols what can come in/out of the cell

Function is to give support to the cell and control what comes in/out of the cell

Nucleus

Wrapped in a phospholipid membrane with small openings called nuclear pores

These pores allows some materials eg rna to pass through it

Contains Dna in structures called chromosomes

Contains nucleolus

Function is the control centre of the cell and nucleolus makes rna

Mitochondrion

Has and outer membrane and an inner membrane

The inner membrane is folded into structures called cristae

The more folds the more energy it can release

Contains a loop of dna seperate of that to the nucleus

Responsible for respiration which is the release of energy from food

Ribosome

Some of the smallest organelles in the cell

Made up of ribosomal rna and proteins

It is not membrane bound

Function is protein synthesis

Endoplasmic reticulum

Membrane bound organelle that consists of a set of interconnected tubes called cisterae

Smooth ER -lipid synthesis and stores calcium

Rough ER - protein synthesis

Responsible for proteinand lipid synthesis and stores and releases calcium

Golgi apparatus

Consists of stacks of membrane bound sacs called cristae- not interconnected like the ER

Responsible for packaging the proteins and lipids manufactured in the ER

Ultrastructure

Fine details of a cell that can be seen with an electron microscope

Cell wall

Made up of a complex carbohydrate called cellulose

Fully permeable which means it allows all substances to pass through it

Middle lamella is the space between cells and has pectin which holds cells together

Gives support and strength to the cell

Chloroplast

Double membrane with liquid in it called stroma and thylakoids

Stack of thylakoids called a granum

Chlorophyll within the grana

Responsible for photosynthesis

Vacuole

Filled with a fluid called cell sap which contains water dissolved sugar and salt and waste materials

Large permanent vacuole in plant cell

Large vacuole gives plants strength by pushing against the cell from within this pressure exerted is called tugor

Ocular lens

Magnifies specimen

Specimen is viewed through here

Objective lens

Magnifies specimen

Low-high power

Stage

Holds the slide

Coarse focus wheel

Brings specimen into rough focus

Fine focus wheel

Brings specimen into sharp focus

Light source

Provides light to view specimen

Iris diaphragm

Controls amount of light shining on the specimen

Cover slip

Prevents specimen from drying out

Keeps specimen in place

Protects the lens from stain