Cell Biology

Eukaroytic Cells- Animals,Plants, Fungi, Protista

Cell Membrane, Cytoplasm, Genetic Material (IN NUCLEUS)

Form stuctures (Chromsomes) (IN NUCLEUS)

Prokaryotic Cells- Bacteria (Single Celled)

Cell Membrane, Cytoplasm, Cell Wall                                                            Genetic Material (Single DNA LOOP) (IN CYTOPLASM) (NOT IN NUCLEUS)Small Rings Of DNA (Plasmids)

Animal Cells  10-30 micrometres long

Nucleus-  Controls activities of cell, contains genes of chromosomes

Cytoplasm-  Chemical Reactions take place

Cell Membrane- Controls passage of substances (glucose, mineral ions)

Mitochondria- Structures where aerobic respiration happens, provide energy for the cell, found in cytoplasm,1.2 micrometres (length), 0.2-0.7 (diameter)

Ribosomes-Where (protein synthesis) happens, makes proteins for the cell

Plant Cells- 10-100 micrometres long

Cell Wall (cellulose)- Strengthens and supports cell

Chloroplasts- Found in (green parts) of cell, (green colour) as contain chlorophyll - absorbs light to make food through (photosynthesis), Chloroplasts (3-5 micrometres) long

Permanent Vacuole- Filled with (cell sap) to keep cell (rigid)

SPERM CELL-  take the MALE DNA to the EGG

• Tail to help it swim to egg
• Lots of mitochondria- provide energy for swiming

NERVE CELL- carry ELECTRIC SIGNALS around the BODY

• Long to cover more distance in body
• Branches at end to connect to others

MUSCLE CELL- contract (SHORTEN)

• Long so they have space to contract
• Lots of mitochondria- provide energy for contracting

ROOT HAIR CELLS- absorb WATER and MINERALS

• Grow into 'long hairs' that stick out into the soil
• Gives plant a 'big surface area' for absorbing water and mineral ions from the soil

PHLOEM CELLS- transport FOOD    XYLEM CELLS- transport WATER

• They form phloem and xylem tubes

• To form them, the cells are long and joined end to end
• Xylem- (HOLLOW)
• Phloem-(LOTS OF SPACE INSIDE)

DIFFERENTIATION- Where cells CHANGE to become SPECIALISED

As cells CHANGE, they develop DIFFERENT SUBCELLULAR STRUCTURES, turn into DIFFERENT TYPES OF CELLS, allows them to carry out SPECIFIC FUNCTIONS

Usually occurs as organism DEVELOPS

ANIMAL CELLS-

• Can only DIFFERENTIATE at an EARLY STAGE of animal's life

PLANT CELLS-

• DIFFERENTIATE for WHOLE of plant's life

UNDIFFERENTIATED CELLS- STEM CELLS

The USE OF MICROSCOPES have DEVELOPED as TECHNOLOGY and KNOWLEDGE have IMPROVED

LIGHT MICROSCOPES-

• Used to LOOK AT CELLS
• Let us see LARGE SUBCELLULAR STRUCTURES (NUCLEUS)
• LOWER RESOLUTION

ELECTRON MICROSCOPES-

• HIGHER RESOLUTION- show things in MORE DETAIL
• HIGHER MAGNIFICATION- let us see REALLY SMALL THINGS (RIBOSOMES, PLASMIDS)

INVENTION-

• 1ST - LIGHT

• 2ND- ELECTRON
• Helped scientists UNDERSTAND MORE about SUBCELLULAR STRUCTURES

MAGNIFICATION =   IMAGE SIZE ÷ REAL SIZE

IMAGE SIZE =         MAGNIFICATION  x   REAL SIZE

REAL SIZE =             IMAGE SIZE ÷ MAGNIFICATION

MICROMETRES to MILLIMETRES   =    ÷ 1000

RESOLUTION=   Ability to DISTINGUISH between TWO POINTS

                    HIGHER RESOLUTION = SHARPER IMAGE

DESCRIPTION:  Use a LIGHT MICROSCOPE to OBSERVE, DRAW and LABEL a SELECTION of PLANT/ANIMAL CELLS

EQUIPMENT:                                                    STEPS

• LIGHT MICROSCOPE           1.Peel off a LAYER OF ONION and
• ONION                                               place it on a MICROSCOPE SLIDE
• KNIFE                                              2. Add a DROP of IODINE SOLUTION
• FORCEPS                                            and cover with a COVER SLIP
• COVERSLIP                                    3. ADJUST the COARSE ADJUSTMENT
• SLIDE                                                  KNOB until the CELLS come into 
• IODINE SOLUTION                             FOCUS and ROTATE  the                                                              OBJECTIVE LENS so that it's                                                              the most POWERFUL                                                 4. Draw the cells seen and label with STRUCTURES and MAGNIFICATION