The dna gives the instructions of how the cell should function.
There are sections called genes in dna - they are what give the characteristics of a being.
- (eg: blue eyes, black hair, height, ect…)

Mitochondria: powerhouse of the cell.

Where energy is made
Cellular respiration formula:glucose + oxygen → carbon dioxide + water + energy ATP

Chloroplast:

Only found in animal cells
Used in photosynthesis → where plants make glucose
Water + carbon dioxide → glucose + oxygen
Contains chlorophyll - this is what makes plants green.

Rough ER (rough endoplasmic reticulum):

has ribosomes on it - ribosomes are what make proteins

Smooth ER (smooth endoplasmic reticulum):

Makes steroids and lipids
No ribosomes
Is next to the rough ER

Golgi body / golgi apparatus:

Takes the stuff made from the ERs
packages it into vesicles
Vesicles move from the golgi body to the cell membrane to release the contents

Lysosomes:

‘Garbage / recycling’
Sorts useful and not useful substances
Takes out what isn’t needed
Only in animal cells

Vacuoles:

Both plant and animal cells
- Plant cells have 1
- Animal cells can have many
Storage center for water and nutrients
Expands to full capacity when water is in it
TURGIDITY is what its called when the cell is ‘swollen’

Cell wall:

Only in plant cells
Made of cellulose
Keeps cell structured, strong and stable

Cell membrane:

Is a layer encompassing the entire cell that allows substances in and out of the cell. The level of selectivity of molecules is called permeability.
- Permeable - allows all molecules to pass through the cell membrane
- Impermeable - does not allow any molecules to pass through
- Selectively permeable - only certain molecules can pass through (most are semipermeable)

The cell membrane is made up of hydrophilic heads and hydrophobic tails.
- The hydroPHOBIC tails are fatty acids meaning they repel water
- The hydroPHILLIC heads like water

As shown in the diagram above, there are channels throughout the cell membrane that allow water to pass through and enter the cell without interference with the hydrophobic tails.

Different cellular structures

Prokaryotic vs eukaryotic cells

describe a range of technologies that are used to determine a cell’s structure and function

Types of microscopes

characteristics	Light microscopes	Sem - scanning electron microscope	Tem - transmission electron microscope
magnification	Can be calculated by multiplying the magnification of eye piece by objective lens. Can effectively magnify x1500 (10x - 400x of school ones)	Magnified x10 - 3,000,000	Magnified X1,500,000 with a resolution of 2nm
Light source	Light bulb	electrons	electrons
Cell parts that can be observed	Shape of cell and some organelles. (Nucleus (if chemically stained)).	The outside of a cell - not the organelles
cost	Cheap (300 - 400 aud)
Specimen type	Both living and non living. Can be viewed in color

Investigate a variety of prokaryotic and eukaryotic cell structures, including but not limited to:

drawing scaled diagrams of a variety of cells

comparing and contrasting different cell organelles and arrangements

modelling the structure and function of the fluid mosaic model of the cell membrane

cell function

cell structure

plant or animal
major organelles visible with light from an electron microscope
membrane structures

prokaryotic vs eukaryotic cells

types of cells

eukaryotic and prokarytic
technologies to understand cells

cell function

stuff gets in and out
- diffuction & osmosis
- active and passive transport
- endocytosis & exocytosis
- importance of SA/Vol (surface area/volume)
food and energy for cells
- photosynthesis
- cellular respiration
- what cells need
biochemical control enzymes
- properties of enzymes
- effects of temperature & pH on enzyme activity

metabolism

the total sum of all chemical reactions occurring within a living organism, each step of a metabolic pathway in cells is catalyzed by enzymes

2 types of metabolism

anabolic:

building up large organic compounds from smaller elements/molecules
eg: making a protein from amino acids, making a polysaccharide (ie starch) from monosaccharide units (ie glucose)

catabolic

breaking down complex organic compounds into simpler ones
eg: breaking down glucose for energy, digestion of food

enzymes

enzymes are proteins. proteins are long chains of amino acids joined by peptide bonds (polypeptide), folded into a 3d shape that it relies on for its functioning.

enzymes are biological catalysts, they control the rate at which a reaction takes place. an animal cell can have up to 4000 different types of enzymes, each one responsible for its own reaction for a particular function.

General

characteristics

temperature (heat and cold)
pH (acidity or lack of acidity in a substance)
Substrate concentration

shape

each type of enzyme has a specific shape out of a specific pattern of amino acids. Enzymes have an active site that are normally made up of 3 or 4 amino acids, these active sites are what the substrate latches on to (forming a new molecule (enzyme-substrate complex).

role

speed up reactions without a change in temperature
lower activation energy to begin the reaction (bringing specific molecules together rather on relying them on randomly colliding)

activation energy

molecules need to collide at the right energy and orientation for a reaction to take place

models for how enzymes work (specifically on substrates):

lock and key model theory

It WAS thought that an enzyme’s active site could not be changed and that the substrate fit like a lock and key (key A fits lock A, key B fits Lock B).

Once the enzyme-substrate complex was formed, the reaction could occur and the products were released.

induced-fit model theory

The lock and key model of forming enzyme-substrate complexes isn’t always the case.

The induced fit theory assumes that the substrate plays a role in specifying the final shape of the enzyme-substrate complex. This means that the active site is a lot more flexible and complex than previously thought.

the substrate enters and binds to an enzyme to mold it and fit into each other to create a reaction (other substrates can enter the active site, however unless they are properly able to shape then enzyme a reaction will not occur).

coenzymes

many enzymes need a coenzyme to function. A coenzyme is a nonprotein group such as a vitamin or a metal ion that binds the protein part to help form the active site, it increases the size of the enzyme molecule and can be easily separated from it enzyme.

A functional enzyme could only consist of protein, or only in the form of an enzyme-cofactor complex.

denaturing

Syllabus dot point (1.2.5) - investigate the effects of the environment on enzyme activity through the collection of primary or secondary data

Denaturing is a permanent altercation of an enzyme in which the enzyme cannot function properly. Substrates wont be able to bond with the enzyme as it is changed in shape.

temperature sensitive

heat - enzymes function at about 37°C, above 60°C they will become denatured where the shape and structure begin to change PERMANENTLY.

cold - extreme cold can cause enzymes to slow down or stop functioning altogether, but this is NOT PERMANENTE. Once the temperate returns, the enzyme will resume normal functioning.

Ideal temperature - not all enzymes have the same preferred tempurater, in mammels, enzymes peak at what is the normal body temperature. Plant enzymes would have a much wider range of temperatures.

pH-sensitive

each enzyme has an ideal pH, this level varies greatly from enzyme to enzyme. If the pH is too low or too high, then the reaction rate is lower as the substrate no longer fits.

substrate sensitive

enzyme molecules are specific, only 1 type of substrate can bond with an enzyme, and each enzyme catalyses 1 type of chemical reaction. the rate of the reaction involves the density of the substrate, substrate concentration is the amount of compound present that the enzyme needs to catalyse.

Enzymes can be used multiple times for different substrates, but if the substrate concentration is too high, then the rate of reaction is constrained by the amount of enzymes.

rate of reaction

enzymes are highly efficient catalysts, they work rapidly to break apart and form new bonds.

Enzyme activity will increase as the substrate concentration increases, eventually though the enzyme activity will platue as they are all being used and are ‘working’.

This maximum rate that which enzymes can work is called the saturation point.

if more enzymes were added the reaction rate would increase until its reached the saturation point once again.

Knowt