The cell

What is a cell

Structural and functional unit of all living organisms

Unicellular

One cell

Example of unicellular

Bacteria

Multicellular

Many cells

Example of multicellular

Plants, animals, humans

Prokaryotic

Generic material, not membrane bound, cytoplasm contains no distinct organelle

Eukaryotic

Genetic materials contained in nucleus, cytoplasm contains separate organelles

Interstitial space

Space between cells

Interstitial fluid

Fluid around and in between cells

What does interstitial fluid provide for cells

Nutrients and means of waste removal

Structure of cell membrane

Surrounds cytoplasm, separates and protects the cell, membrane made up of phospholipids that form a bilayer when added to water, membranes are dynamic

Hydrophilic

Water loving, head group

Hydrophobic

Water hating, tail group

What is embedded in the cell membrane

Cholesterol, proteins

Cholesterol

Adds stability

Protein roles

Act as specific receptors, regulate what is transported across the membrane in and out of cell

Passive transport

Substances move down concentration gradient form high concentration to low concentration

Active transport

Energy is required to move substances from low concentration to high concentration

What is bulk transport

Substances are too large to cross the cell membrane

Steps of bulk transport

Taken into cell by pinocytosis/phagocytosis, eliminated from cell by exocytosis

Cytoskeleton

Strands of proteins involved in maintaining the structure of cell

Micro filaments

Structural support, maintains shape of cell

Microtubules

Various molecules are transported within the cell

Nucleus

Continues the chromosome

What begins in the nucleus

Cell replication, protein synthesis

Mitochondrian

Energy generated here, aerobic respiration occurs here which generates ATP which is then used as an energy source in the cell

How does mitochondria replicate

Self replicated as they contain their own DNA

Why does the number of mitochondria in a cell vary?

Depends on the energy requirement of the cell

Lysosome

Contains digestive enzymes which digest substances which are then recycled or released from the cell

What does lysosomes digest

Macromolecules, cellular components, foreign bacteria

Ribosomes

Synthesis proteins within our cells

Where are ribosomes located

Cytoplasm, bonded to nuclear envelope or endoplasmic reticulum

What are the types of endoplasmic reticulum

Smooth and rough

Smooth ER

Synthesis lipids, steroid hormones, metabolise carbohydrates, detoxification of some drugs

Rough ER

Ribosomes attached, processes protein and transports to cell membrane, protein passes through Golgi apparatus first en route to cell membrane

Golgi apparatus

Further customises, refines and sorts protein