Biology version 2

what 3 solutions do you add into a non reducing sugar?

1. sodium hydrogen carbonate
2. hydrochloric acid
3. benedicts solutions

why is sodium hydrogen carbonate added in a non reducing sugar test?

in order to neutralise the hydrochloric acid as benedicts does not work in acidic conditions

why is there a change in colour if there is a non reducing sugar?

reducing sugars are produces from the hydrolysis of non reducing sugar by hydrochloric acid

if there is a reducing sugar what colour does it change?

blue to red

if starch is present what is the colour change?

orange/ brown to black

what solution is added in a starch test ?

iodine

what solution is added in a lipids test?

ethanol

what forms in a positive lipid test?

a milky emulsion is produced due to lipids being dispersed in the water

what is the test for a lipid?

add equal parts of sample, water and ethanol then shake.

What is the test for starch?

Add a few drops of Iodine Solution, gently shake, it should turn from brown/orange to blue/black

how is fatty acid and gylcerol bonded ?

an ester bond formed via a condensation reaction between the carboxyll of the fatty acid and hydroxyll of the gylcerol.

what are the four properties of water ?

- high specific heat capacity
- high latent heat of vaporisation
- good solvent
- adhesion and cohesion

why is water a good solvent? and why is it important?

dipole nature which allows it to form hydrogen bonds with other molecules. it allows water to transport substances around the body.

Why is water having a high specific heat capacity important?

As water has a high heat capacity it requires alot of energy to increase the temperature of 1kg of a substance. This helps maintaning homeostasis preventing blood from heating up.

why is adhesion and cohesion important for plants

the water molecules form hydrogen bonds with other water molecules, the water also binds to the walls of the xylem causing tension that allows capillary action for transpiration.

why is water having a high latent heat of vaporization important?

requires a lot of energy to change a liquid into a gas so when water vaporises it transfers a lot of heat energy cooling a person

what is DNA?

deoxyribonucleic acid, which stores genetic information and has a double helix structure

what are the bases and their complimentary pairs?

Adenine + Thymine
Guanine + cytosine

what is the monomer that makes up dna and what is ts structre ?

nucleotide - base, pentose sugar, phosphate

what is the bond between two nucleotides called and the name for when a pentose bonds with a phosphate.

- phosphodiester bond
- sugar phopshate backbone

How many bonds form between the complimentary bases and which is the most stable?

a,t - 2
c,g -3
more bonds means more stable

what bonding forms between the bases and what does it do?

a hydrogen bond is formed between the bases and it joins the strands together

what are the two enzymes involved in DNA replication

DNA helicase DNA polymerase

What does DNA Helicase do in DNA replication?

breaks down the hydrogen bonds between the bases splitting the strands.

what does DNA polymerase do?

it causes a phosphodiester bond to form between the nucleotides

what happens to free nucleotides in DNA replication?

free nucleotides pair up with their complimentary bases forming a hydrogen bond using atp

what is the structure of ATP ?

adenine, ribose, 3 phosphate groups

what is the difference between a nucleotide and atp

- Atp has 3 phosphates
- Atp has adenine, but dna can have any
\-

what is the structure of rna

-ribose sugar
-nitrogen bases
-phosphate group

what is the difference between dna and rna ?

- dna is double stranded, whilst rna is single stranded
- dna bases : a,c,t.,g rna bases: a,u,c,g
-dna has deoxyribose sugar , rna has ribose sugar
- dna is longer than rna

what can Atp be hydrolysed into

adp and and an inorganic phosphate plus energy

What enzyme produces ATP?

ATP synthase

what is a catabolic enzyme?

an enzyme that breaks large molecules into small molecules

what is an anobolic enzyme

an enzyme that builds up small substrate into large substrate

What is the induced fit model?

the active site is flexible and can sometimes change shape to fit the substrate

what forms between the active site and substrate? and what 2 things does it do ?

weak hydrogen bonds form which :
- change the shape of the active site
- weaken the bonding within the substrate which lowers activation energy.

what 4 factors affect enzyme activity?

- temperature
- ph
- enzyme concentration
- substrate concentration

what is a mutation?

a change in the dna base sequencing

what is the structure of beta and alpha glucose?

OH at the top for beta ,OH on the bottom for alpha

what is the structure and function of starch

starch is a polysaccharide made up of alpha glucose which is a storage molecule in plants (1,6) (1,4)glycosidic bonds. it is curved

what is the structure and function of glycogen?

made of alpha glucose and has (1,6) glycosidic bonds and a branched structure. it is used as storage in the liver

what is the structure and function of cellulose?

beta glucose, (1,4) glycosidic bonds, straight chained, microfibrils and chain structure provide strength as a structural component.

what is the bond between monosaccharides called?

glycosidic bonds

what does (1,4) and (1,6) glycosidic bonds do?

1,4 - straight chain
1,6- branched

what is the name of the molecules made from 3 fatty acids and glycerol?

triglyceride molecules

what is the difference between a saturated and unsaturated molecule?

saturated - single bond
unsaturated - double bonds

what ype of bond is formed between the fatty acid and glycerol

carboxyll of fatty acid and hyroxyl of glycerol

what is emulsion

breaking large triglyceride molecules into smaller molecules

what is a phospholipid and its qualities?

a phospholipid \= glycerol + 2 fatty acid + phosphate
qualities:
- hydrophophilic phosphate head and hydrophobic fatty acid tail

what is the difference between a triglyceride and phopholipid ?

- triglyceride has 3 fatty acids, whilst phospholipid 2 fatty acids.
- triglyceride has no phophate attached to glycerol backbone whilst a phospholipid does

what does a phospholipid do?

makes up the cell membrane

what is the positive test for protein?

blue to purple

what bond forms between 2 amino acids

peptide

What is the primary structure of a protein?

sequence of amino acids

What is the secondary structure of a protein?

folding of peptides into alpha helix and beta pleated sheets , which is held by hydrogen bonds between the carboxyl and amin group

what is the tertiary structure?

the 3d structure is affected by the order of r groups. bonding depends on the order of r groups.

what is a globular protien? what is a fibrous protien?

it helps with metabolic reactions metabolic proteins. whilst fibrous proteins are used for structural proteins

Why is ATP useful?

low activation energy so its bonds can be broken easily

what site does a non competitive inhibitor bind with and a competitive

non competitive: allosteric
competitive: active site

What does a competitive inhibitor do?

it has a similar shape as the substrate so it binds to the active site prevent a substrate enzyme complex from forming

What is the weakest bond?

hydrogen bond

Why does temperature affect the rate of reaction?

-it increases the kinetic energy so more frequent collisions occur between the substrate and the active site.
-breaks bonding between r groups changing shape of enzyme

what are bonds between r groups?

disulfide, ionic , hydrogen

Why does pH affect the activity of an enzyme?

the H+ and OH- ions interact with the slight charge found on the active site preventing the active site binding with the substrate

who discovered DNA

Watson and Crick

Who came up with the semi conservative theory?

meselson and stahl

What is the semi-conservative model?

the two strands of the parental molecule separate, and each functions as a template for synthesis of a new, complementary strand

what is a sense strand and anti sense strand?

a sense strand is a template strand , whilst an anti sense strand is the complimentary strand to the template strand

what does it mean that dna is universal ?

the same bases code for the same thing in all organism

what does dna being non overlapping mean ?

one base is in only one codon

what does being degnerate mean?

different codons cod for the same amino acid

What is a condensation reaction?

When two molecules bond through the loss of a water molecule.

What is hydrolysis?

the chemical breakdown of a compound due to reaction with water.

what are the adaptations of starch?

INSOLUBE- does not affect osmotic balance
compact - store large quantities

what is the adaptations of cellulose ?

hydrogen bonds between the straight chains make the saccharide compact
does not allow large molecules to leave

state 3 similarities and between 2 peptides and one difference.

- both have a carboxyl group-
-both have an amin group
- different r groups
- peptide bond between 2 amino acids

What is the nucleus surrounded by?

nuclear envelope, which contains a double membrane

within the double membrane surrounding the nucleus what is there?

nuclear pores which allow large molecules through

what makes ribisomes in the nucleus

nucleolus

What is the function of the mitochondria?

produce ATP during aerobic respiration

what does the inner membrane fold into?

cristae

why does a inner membrane fold into a cristae?

in order to increase surface area for the attachment of enzymes and other proteins for respiration.

what does mitchondria do for aerobic respiration?

link, krebs cycle and oxidative phosphorylation

in mitochondria what happens to the double membrane ?

double membrane is seperated by a fluid filled space

What does the matrix contain?

protein fibers, water, minerals, nutrients, waste products

what does the endoplastic reticulum consist of?

flattened membrane sacs

What does the rough endoplasmic reticulum do?

covered with ribosomes; processes proteins; transports proteins around the cell; proteins are made.

What does the smooth endoplasmic reticulum do?

finishes the lipid making process; transports lipids around the cell

What does the Golgi apparatus consist of?

stack of membrane bound flattened sacs and releases vesicles.

what is the function of the golgi apparatus

modifies proteins from the endoplasmic reticulum and transports them in vesicles.

what is the shape of lysomes

spherical sacs surrounded by a single membrane

what do lysomes do?

contain digestive enzymes which break down material

what type of membrane does chloroplast have and what is its strutcure ?

it has a double membrane.
gana- stacks of disk like structures called thylakoids which house the pigment chlorophyll
- the stroma is a fluid filled matrix

what organelles have a single membrane ?

Lysosome, Endoplasmic Reticulum, Golgi Apparatus, Peroxisome, Vacuoles

what organelles have a double membrane?

in the nucleus, mitochondria, and chloroplasts

What is the magnification of an optical microscope?

1500x

what is the magnification of a scanning electron microscope?

500,000x

what is the magnification of a transmission electron microscope?

500,000x

what is the resolution of an optical microscope?

0.2 um

what is the resolution of a scanning electron microscope?

20 um