Cells as the basis of life

Unit 1 topic 1

Prokaryotic

• simple cell

• unicellular organisms

• little organisation

• not membrane-bound nucleus or organelles

• DNA in the cytoplasm

• circular DNA

• small (6.5-10 micromillimeters)

• Bacteria and Achaea

Eukaryotic

• Complex cells

• unicellular to multicellular organisms

• membrane-bound nucleus and organelles

• DNA in the nucleus

• linear DNA

• larger (30-150 micromillimeters)

• Animalia, plantae, fungi, protists

Autotrophs

organisms that make food from CO₂ and an energy source. They produce food for themselves snd others as well as storing food.

Producers

Heterotrophs

Organisms that are unable to make their own food and must take food from other organims.

Consumers

Nucleus

• Control center of the cell

• contains genetic materials

• produces ribsomes + RNA

• Essential in cell division

Mitochondria

• rod-shaped

• thin membrane

• site of cellular respiration

• powerhouse of the cell

• generate ATP through the conversion of energy from nutrients

Rough + Smoother Endoplasmic Reticulum (ER)

• Extension of the outer nuclear membrane,

• involved in protein and lipid synthesis.

• Forms a transport network through out the cell.

• large surface area for chemical reactions

• Rough ER has ribosomes attached

• Smooth ER is involved in detoxification and metabolism. and produces lipids and steriods.

Glogi Apparatus

• Membrane bound sacs

• produces glycoproteins and secretory enzymes

• Secrets carbohydrates which are used in cell wall production

• Transports and stores lipids

• forms lysosomes

Lysosomes

• Contains + releases digestive enzymes

• helps destroy unwanted or worn-our cell organelles

• digestion of material within cell

• complete digestion of cell after death

Vacuoles

• Fluid-filled saces surrounded by membrane

• Stores sugar and amino acids

Chloroplasts

• Helps with photosythesis

• double strandard DNA molecules

• In plants and proteins

• 3 membranes which allows for compartments that contain the enzymes used in photosythesis

• Chlorophyll absorbs light and converts it into chemical energy.

Unicellular Organisms

• one cell

• preform all functions and activities of life within a single cell

• cell feeds, respires, excretes, is sensitive to internal and external conditions, may move and eventually divides or reproduces

• Examples; Amoeba, Paramecium, etc

Multicellular organisms

• made up of a mass of cells fused together

• cells become specialised to preform special functions

• all have speciliased cells

• allowed by only some genes being expressed - the genes are different for different functions

• Examples; Most living things, including humans

Digestive System

Nutrients:

• Breaks down food and allows movement through the intestines

Ciculatory System

Nutrients

• delivers nutrients to the extracellular fluids and therefore all cells

Gas

• Blood vessels transfer oxygen to the cells and remove CO2

Waste

• Wastes will move around the bloodstream to be removed from the body

Respiratory System

Gas

• lungs allow oxygen to be absorbed from the air and CO2 to be removed from the body.

Waste

• lungs allow CO2 to be removed from the body.

Extretory System

Waste

• Kidneys filter blood to remove waste (via the bladder)

Fluid Mosaic Phospholid Bilayer structure

Phospholipids

• main componenet of membranes

• 2 layers

• phosphate hydrophilic head

• lipid hydrophobic tails

Protein Channels

• integral protein

• transmembrane proteins

• involved in transport, enzymatic action and signla transduction

Cholesterol

• stabilises the membrane

• reduces permeability to small watersoluable molecule

• buffer against changing temperature

Glycoproteins

• carbohydrate attached to a protein

• on the outer surface

• recognition between cells and of antibodies, hormones and virus

Osmosis

• the movement of water from an area of high water concerntraion to an area of low water concerntration

• Passive

simple and facilitated diffusion

Simple

• the movement of molecules from an area of high concerntration to an area of low concerntraion

• Passive

• examples; oxygen and carbon dioxide

Facilitated

• For larger molecultes

• passive

• examples; amino acids, glucose, calcium and sodium ions

Active transport

• molecules moving from an area of low concerntraion to an area of high concerntration.

• moves through proteins channels

• Requires energy in the form on ATP

• moves against the concerntration gradient

• examples; glucose, amino acids, sodium and potassium ions.

endocytosis

• transports substances into the cell

• requires energy

• Phagocytosis and Pinocytosis

• bacteria and cell debris

Exocytosis

• Transport substances out of the cell

• requires energy

• transports waste and digestive enzymes

Passive and Active Transport

Passive: when a system (like osmosis) doesn’t require energy to be able to take place/ transport what’s being moved.

Active: when a system needs energy to take place/transport what needs to be moved.