Biology- Units 1/2

Whats a monomer

A small chain of repeating units

What elements do Carbohydrates contain

Oxygen, Hydrogen, Carbon

Whats the difference between a saturated bond and an unsaturated bond

Saturated contains no carbon carbon double bond but an unsaturated bond does

Whats a hydrolysis reaction

The breaking of bonds by addition of H20 between 2 molecules

What does a Reducing sugar test, test for

Monosaccharides

What does a non reducing sugar test, test for

Di/polysaccharades

What does iodine show there is included

Starch

Name three variables in a sugar test that have to make sure have been adhered to

1) volume of Benedict’s solution

2) duration of heating

3) water bath temp

Whats a positive result for a reducing sugars test

Red precipitate

If the reducing sugars test is negative what must you do to complete a non reducing sugars test

Boil with acid and neutralise with NaHCO3

Heat with Benedict’s solution

Positive result is red precipitate

In a dilution series what does a high absorption mean

More sugar is present

In a calibration graph what do the axis represnt

X- conc of (glucose) solution

Y- absorption

Whats an amino acid

the monomers from which the polymer proteins are made

What does NH2 represent

The amine group

What does COOH represent

The carboxyl group

What does R represent

the variable group which distinguishes between the amino acid

What 4 elements are in the basic structure of an amino acid

Carbon, Hydrogen, Oxygen and Nitrogen

What bonds do dipeptides form

Peptide bonds

In a chain of amino acids what is free at either end

An amine group and a carboxyl group

what is the primary structure

the order and sequence of amino acids in a polypeptide chain formed by peptide bonds

whats the calculation for the number of peptide bonds in a peptide chain

number of amino acids - 1

how many different amino acids are there

20

What bonds are involved in the secondary structure

Hydrogen bonds

What 2 structures does the secondary structure form

1) alpha helix 2) beta pleated sheets

Whats the alpha helix’s shape

Coiled

Whats the beta pleated sheets shape

folded

whats the tertiary structure formed by

interactions between the R groups and positive and negative charges in different parts of the molecule

What are the bonds in the tertiary structure

hydrogen, disulphide, ionic

Explain disulphide bridges

the strongest bond as they are covalent between 2 sulphur containing amino acids

whats the quaternary structure

proteins containing several different polypeptide chains

how is the quaternary structure decided

by the way the polypeptide chains are assembled together

what does the primary structure determine

the tertiary structure

breifly explain 4 functions of proteins

1) enzymes, spherical shape, soluble and involved in metabolism

2) antibodies, 2 short and 2 long polypeptide chains in the immune response

3) transport, hydrophobic/phillic amino acids form a channel so transport molecules and ions across membrane

4) structural, strong with parallel chains and cross links

whats the test for proteins and what does a positive test show

Biuret test, colour change to purple

whats an enzyme

a biological catalyst

what must an active site be to a substrate and why

Complementary because it forms enzyme substrate complexes

what happens to the activation energy when enzyme substrate complexes and why

reduces because bonds are stressed

what are the 2 hypothesis of enzyme action

1) lock and key 2) induced fit

what happens in the lock and key method

the enzyme’s active sight is precisely shaped to fit the substrate

what happens in the induced fit model

the tertiary structure of the enzyme changes shape to better fit the substrate

How does the tertiary structure relate to the enzyme [6]

• enzymes are very specific so catalyse only one reaction

• because only 1 complementary substrate fits the active site

• the active site is determined by the tertiary structure

• each enzyme has a different tertiary structure and active site so cant form enzyme substrate complexes with other structures

• if the tertiary structure changes so will the active site so the substrate wont fit

• the tertiary structure changes by pH or temp

what happens when the enzyme concentration increases

rate of reaction increases due to more successful collisions between the active site and substrate forming more enzyme substrate complexes

whats the limiting factor and why is it limiting

the substrate concentration. there are not enough active sitesfor all the available substrates to form enzyme-substrate complexes. The graph would plateau

what happens when the substrate concentration increases

the rate of reaction increases so are more successful collisions between the active site and the substrate so more enzyme substrate complexes are formed

whats the limiting factor and why is it limiting

the enzyme concentration is limiting because all active sites will be full so additional substrate won't increase the rate and the reaction rate will plateau

what happens when the temperature increases

rate of reaction increases as there is more kinetic energy so more enzyme substrate complexes form

what happens when temperature goes over optimum

vibrations break some of the bonds holding the enzymes structure in shape. The active site changes so substrates no longer fit together and the enzyme denatures

whats optimum temperature

37^oC

what bonds are broken when kinetic energy increases

hydrogen bonds between the R groups

what are the 4 effecting factors of enzyme controlled reactions

• enzyme conc

• substrate conc

• temp

• pH

what happens at extreme pH

They denature and hydrogen bonds between the R groups break altering the shape of the active site so less enzyme substrate complexes form

what are the two types of inhibitors

competitive and non-competitive inhibitors

what happens to the rate of an enzyme controlled reaction when using a competitive inhibitor

it decreses

what does a competitive inhibitor do

it binds to the active site because it has a similar shape to the substrate so prevents enzyme substrate complexes

what does the different concentrations mean with a competitive inhibitor

a high CI conc means nearly all active sites filled

what happens to the rate of an enzyme controlled reaction with a non competitive inhibitor

it reduces

what does a non competitive inhibitor do

attaches to the allosteric site which changes the tertiary structure so changes the shape of the active site so its no longer complementary so no enzyme substrate complexes can form

whats an intracellular enzyme

they are enzymes that function within the cell

whats an extracellular enzyme

they are enzymes that function outside the cell, often in the digestive system, catalysing reactions

what is phosphorylation

the addition of a phosphate group to a molecule using ATP. it makes substrates more reactive. can change an enzymes tertiary structure so the active site is complementary to the substrate

What is magnification

Magnification is the process of increasing the size of the appearance of an image

What is resolution

the ability to distinguish between two separate points

what are five facts about an optical microscope

1) it can show colour 2) it uses light 3) it has a lower resolution 4) can view the live specimine’ 5) you can only see basic structure like nucleus

What are five facts about an electron microscope

1) it shows black and white images 2) it uses electrons 3) it has a higher resolution 4) can view non-living specimens 5) allows observation of organelles

what are the 2 electron microscope types

Scanning and transmission

3 facts about the scanning electron

1) electrons bounce off the surface 2) 3D image 3) lower resolution

3 facts about transmission electrons

1) electrons pass through the object 2) 2D 3) Higher resolution

Whats the order to get to from cells to organs

cells to tissue to muscles to organs

Whats the cell surface membrane

outermost membrane surrounding the outside of a cell made from a phospholipid bilayer. some have it as a folded membrane (microvilli) which increase surface area

Describe the nucleus

It stores genetic information to produce proteins and it also controls the cells activities. It has a nuclear envelope which is a double membrane. It has nuclear pores allowing RNA to exit the nucleus. Chromosomes are made from chromatin which code for protein synthesis

Whats the function of mitochondria

Site of aerobic respiration. Synthesises ATP and provides energy for the cell's activities. They are usually found in large numbers

Whats the structure of mitochondia

Its an oval shape which is a double membrane. The inner membrane is folded into cristae where ATPsynthase is embedded. The fluid is called the matrix. It contains its own circular DNA and smaller ribosomes

Whats ATP made from

Ribose, adenine and 3 phosphate groups

Whats ATP hydrolase

Separares ATP into ADP as Pi is released to phosphorylate other compounds

Whats the function of Chloroplasts

Site of photosynthesis in plants and algae. Some in grana and some in stroma

Whats the structure of Chloroplasts

Its flattened and has a double outer membrane. It contains its own circular DNA and smaller ribosomes. It contains a starch grain so store alpha glucose. The fluid region is called a stroma and is made of grana which contain chlorophyll pigment

Whats the golgi body structure

Flattened layers of membrane bound sacs called cisternae and vesicles

Whats the function of the golgi body

Modifies and processes triglycerides by combining them with proteins and packages them for release via exocytosis. It forms lysosomes and vesicles to secrete proteins via the membrane. It joins sugars and polypeptides to form glycoproteins

Whats a lysosome structure

Small round membrane bound organelles

Whats the function of a lysosome

contain hydrolytic enzymes when fused with a vesicle. They digest invading cells and remove dead/worn out cells

Whats the structure of a ribosome

Made from RNA and proteins forming two subunits.

Whats the function of a ribosome

The site of protien synthesis

Whats the Rough endoplasmic reticulum structure

flattened sacs of membrane stacked together with ribosomes attached

Whats the rough endoplasmic reticulum function

It synthesizes and processes proteins.

Whats the smooth endoplasmic reticulum structure

flattened sacs of membrane stacked together

Whats the smooth endoplasmic reticulum function

It synthesizes lipids and detoxifies toxins

Whats the cell wall function

It provides support and protection to plant cells.

Whats the cell wall structure

In plants and algae its made from cellulose and in fungi its made from chitin

what are 4 things a prokaryotic cell has that a eukaryotic cell doesnt have

1) smaller ribosomes 2) no nucleus 3) cytoplasm that lacks membrane bound organelles 4) cell wall containing murein

What are the prokaryotic cells ‘organelles’

plasmids, a capsule surrounding the cell and flagellum

What does the capsule do (prokaryotic cell)

protection from antibiotics

Whats a virus

Acellular non living cell

What does a virus’ structure include

Genetic material, A capsid, Attachment proteins

What does HIV contain

Reverse transcriptase