Compare and contrast a plant and animal cell.
Plant: Larger in size, consists of nucleus, nucleolus, cell wall, plastids (chloroplasts), large vacuole and cytoplasm.
Animal: Smaller in size, consists of nucleus, nucleolus, cell membrane and cytoplasm. Does not have cell wall, plastids and smaller vacuole.
Substances found inside the cell: organic (what does it mean?)
Organic: contains carbon
Lipids, carbohydrates and proteins.
Non-organic substances in the cell
Water, oxygen and salts (ions).
Respiration word formula?
Glucose + oxygen —> carbon dioxide + water + ATP
What is the best model for cell membrane?
Fluid Mosaic Model
Some characteristics of water:
- best universal solvent
- colourless, allows light to penetrate
- high surface tension and low viscosity
- forms droplets on surface, flows freely through narrow vessels.
What are Carbohydrates? What are they made from?
- Sugars (carbon, oxygen and hydrogen)
- used in structural components (cellulose)
- energy storage (starch)
- cellular recognition
Example of Carbohydrates:
- Monosaccharide: Single unit of sugar (eg. glucose, Ribose, Fructose)
- Disaccharides: pair of Mono. (eg. lactose, sucrose)
- Polysaccharides: Long chains of mono. (eg. starch, cellulose)
Explain hydrolysis and condensation:
Hydrolysis: Splitting of compound sugars, back into mono. releases energy but requires water.
Condensation: Monosaccharides joining into di or polysaccharides. Releases water.
What are proteins (made of?) and give examples.
Carbon, hydrogen, oxygen ad nitrogen.
- Made from Amino Acids –> linked by Peptide bonds –> polypeptides
- most abundant in the cell, workforce
- can be structural (collagen)
- catalytic (enzymes)
- movement, transport, storage, growth and repair.
Structure of Proteins
- Primary: sequence of amino acids
- Secondary: initial coiling or folding
- Tertiary: linking of side chains, final protein shape
- Quaternary: Final protein shape for more than one chain.
Purpose of Nucleotides/ nucleic acids
2 types: (Ribose sugar, Nitrogenous Base and Phosphate)
- Nucleotide: single unit used to make DNA and RNA
- Nucleic Acids: long chains of Nucleotides
DNA: Deoxyribonucleic acid
- found in nucleus
- have double strand of nucleotides
- Thymine, Guanine, Cytosine, Adenine
- no oxygen
RNA: Ribonucleic Acid
- found throughout cell
- part of protein structure
- single strand, has oxygen
- Adenine, Guanine, Uracil and Cytosine
How is information coded in DNA
Through variation in the base sequences (ATCGGTA)
What does Nucleotides do?
encode information for construction, functioning of organism, uses energy currency of ATP
What are Lipid made of and what do they do?
Lipids (Carbon, hydrogen, oxygen)
- repels water
- waxy, oily or greasy
- more hydrogen than carbs/protein –> more energy
- source of energy/fuel
- consists of hydrophilic head, hydrophobic tail
Examples of Lipids:
- Waterproofing (cuticle on plants)
- fat absorbs shocks (protection around vital organs)
- energy storage
- insulation (stored fat, seal blubber)
- cell membrane (provides fluid and permeability.
What is an enzyme?
- type of protein
- catalyst in metabolic reactions
- bonds molecules together
What is Osmosis? is it passive or active?
- type of diffusion of water
- passive
- movement of water from low/high concentration gradient
- between semi permeable barrier
What is Diffusion? Passive or active?
- movement of molecules from one solution to another
- concentration gradient (difference in concentration between 2 areas)
What is Surface area to Volume ratio and how does it affect rate of movement
- the amount of surface area compared to volume
- cells volume increase: ability to absorb materials from surroundings decrease
- larger difference between SA:V is good
- cells need to function between rate of removal of waste–> absorbtion of nutrients
- that is why cells are small–> humans are not one big cell
- increase in efficiency of movement of substances
Meanings of isotonic, hypotonic and hypertonic
Isotonic: balanced concentration
Hypertonic: high salt concentration
Hypotonic: low salt concentration
* refers to water movement
