Unit 1

parts of plant and animal cell

1. cell surface membrane

2. cytoplasm

3. nucleus

4. rough endoplasmic reticulum

5. smooth endoplasmic reticulum

6. ribosomes

7. GA

8. mitochondria

parts of animal cell

numerous small vacuoles

parts of plant cell

• chloroplast

• cellulose cell wall

• large central vacuole

characteristic of cell surface membrane

• made up of lipids and proteins

• selectively permeable membrane allows control of movement of substances in and out of cell

characteristic of cytoplasm

• jelly-like substance

• site most cell activities occur

characteristics of nucleus

• double-membranes organelle

• contains genetic info in the form of chromosomes

• controls cell activities & essential for cell division

characteristics of rough endoplasmic reticulum

• continuous with nucleus

• network of flattened spaces lined with a membrane

• synthesis and transport proteins made by ribosomes

characteristics of smooth endoplasmic reticulum

• more tubular than RER

• synthesise fats and steroids & detoxification

characteristics of ribosomes (free and bound)

• small round structures

• free: synthesise protein used within cell

• bound: synthesise protein transported out of cell

characteristics of golgi apparatus

• stack of flattened disc-shaped spaces surrounded by membranes

• chemically modified substances from ER & stores and packages these substances into vesicles for secretion out of cell

characteristics of mitochondria

• small sausage-shaped organelles

• carries out aerobic respiration to produce ATP for cellular activities

characteristics of cellulose cell wall

• enclosed entire cell

• made up of cellulose

• fully permeable

• protect cell from injury and gives it a fixed shape

characteristics of chloroplast

• oval structures

• contain chlorophyll for photosynthesis

characteristics of large central vacuole

• fluid-filled space enclosed by a partially permeable membrane

• contains cell sap that stores dissolved substances

characteristics of numerous small vacuoles

store food and water temporarily

process of protein synthesis

1. proteins are synthesised by the ribosomes attached on the outer surface of the RER

2. newly synthesised protein is drawn into the lumen of RER

3. vesicles containing proteins pinch off from the ER

4. vesicles fuse with the GA, releasing proteins made by the ER which may be modified +/- sorts, packages and transports proteins

5. secretory vesicle containing the modified proteins punch off from the GA and move towards the cell surface membrane 

6. secretory vesicles fuse with CSM and the proteins exit the cell 

define differentiation

a cell becomes specialised for a specific function

function of red blood cell

• transport oxygen from lungs to all parts of body

• carry CO2 and waste back to lungs

structural features of red blood cell and their function

• contains haemoglobin —> binds reversibly to oxygen for transportation around the body 

• biconcave shape —> increases SA:vol ratio so oxygen can diffuse in and out of the cell at a higher rate

• absence of nucleus —> contain more haemoglobin for transport of oxygen

• flexible —> can squeeze through narrow blood capillaries easily

function of root hair cell

absorb water and mineral salts from the soil

structural features of root hair cell and their function

• long and narrow root hair —> increase SA:vol ratio to absorb water and dissolved mineral salts faster

• cell sap has lower water potential than soil solution —> allow water to enter root hair cell via osmosis 

function of muscle cell

contract to generate movement

structural features of muscle cell and their function

• has contractile fiber —> contract and relax to bring about movement 

• contain many mitochondria —> provide energy for contraction to muscle cell

• has many nuclei —> allow for cell division 

function of carbohydrates

• substrate for respiration for energy

• form supporting structures 

• form nucleic acid

• synthesise nectar and lubricants

state why starch and glycogen are suitable as storage materials

• insoluble in water —> do not change water potential in the cell

• large molecules —> cannot diffuse through CSM and be lost from the cell

• easily hydrolysed into glucose when needed

• made up of molecules that have compact shape —> occupy less space

function of lipids

• source and long-term storage material (have higher energy value than carbs)

• insulating material —> prevents excessive TE loss

function of proteins

• synthesise new cytoplasm for growth and repair of worn-out cells

• synthesise enzymes and some hormones

• form antibodies to combat diseases 

revise types of molecules in notes

characteristics of protein structure

primary structure

• Unique sequence and no. of AA held together by peptide bonds

secondary structure

• parts of a polypeptide folded into alpha helix and beta pleated sheet 

tertiary structure

• unique 3 dimensional globular structure

quaternary structure

• 2 or more pptd chains joined together

type of bonds for each protein structure

• primary: peptide bonds

• secondary: hydrogen bonds between peptide bonds

• tertiary: HHID between R grps

• quaternary: HHID

composition of an amino acid

• CH grp

• acidic/carboxyl grp

• amino grp

• variable R grp

bond for lipids and its chemical formula

ester bond (COO)

bond for protein and its chemical formula

peptide bond (CHON)

bond for carbohydrates and its chemical formula

glycosidic bond (COC)

revise food tests on bio doc

definition of diffusion

net movement of particles from a region of higher concentration to one of a lower concentration, down a concentration gradient, until equilibrium is achieved

definition of osmosis

net movement of water molecules from a region of HWP to one of a LWP through a partially membrane

definition of active transport

net movement of particles from a region of higher concentration to one of a lower concentration, against a concentration gradient through a selectively permeable membrane

factors affecting rate of diffusion

• concentration gradient

• diffusion distance

• SA:vol ratio

factors affecting rate of osmosis

• water potential gradient

• Distance for osmosis

• SA:vol ratio

factors affecting rate of active transport

• energy in the form of ATP from respiration

• presence of cell membrane

definition of water potential

measure of tendency of water molecules to move from one place to another

revise movement of substances in bio doc

describe the process of a plant cell in a solution of HWP

1. cell sap has lower water potential than surrounding solution

2. net movement of water into the cell by osmosis through partially permeable membrane

3. cell expands and becomes turgid

4. vacuole increase in size and push cytoplasm against cellulose cell wall

5. cellulose cell wall prevents cell from lysing as cytoplasm volume increases

describe the process of a plant cell in a solution of LWP

1. cell sap has higher water potential than surrounding solution 

2. net movement of water out of cells by osmosis through partially permeable membrane 

3. cell becomes flaccid 

4. vacuole decrease in size

5. CSM shrinks away from cell wall and cell becomes plasmolysed 

describe the process of animal cell in a solution with HWP (RBC)

1. cytoplasm has lower WP than outside solution 

2. water molecules enter by osmosis through partially permeable membrane 

3. cell expands and burst

describe process of animal cell in solution with LWP (RBC)

1. cytoplasm has higher WP than outside solution 

2. water molecules leave by osmosis through partially permeable membrane 

3. cell shrinks in size and crenates 

definition of catalyst

substance that can speed up a chemical reaction without itself being chemically changed at the end of the reaction 

function of enzymes

catalyse rate of chemical reactions by lowering activation energy needed to start them and remain chemically unchanged at the end of the reactions

what are enzymes

• proteins that act as biological catalysts

• fold to take on 3D globular shapes 

definition of activation energy

energy needed to start a chemical reaction

type of enzyme catalysed reaction and their function

1. anabolic reactions

• cells build up complex substances from simpler ones (ie protein synthesis)

2. catabolic reactions

• cells break down complex substances to simple substances (ie digestive enzymes)

characteristics of enzymes

1. enzymes speed up chemical reactions

• lower activation energy needed to start a reaction

2. enzymes specific in action

• have active sites; only substrates with shape complementary to active site can fit into enzymes 

• enzyme binds to substrate —> ESC formed

• shape affected by chemicals and high temp.

3. enzymes required in small quantities and remain chemically unchanged at the end of the reaction 

• can be reused again —> small amount can catalyse reaction for large amt of substrate 

4. enzymes affected by temp.

5. enzymes affected by pH

revise answer format in bio doc