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Biology A level

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What elements does carboyhydates consist of


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457 questions
Examples of Monosaccharides
Alpha glucose=
Down up down down H is first down
Beta glucose
= down up down up / H is first up
Monosacharide + monosaccharise=
Disaccharide + water (condensation reaction)
Eg of hydolysis reaction
Sucrose + water= glucose + fructose
Eg of a monasaccharide and uses
Glucose C6H12O6 small and soluble used in respiration for energy
Forms a glycosidic bond + water
Removes water by temp/ optimum temp
What is a polysaccharide
A large polymer of monosaccharide -starch, glucose glycogen -non reducing
Function - strengh and rigidty to the cell wall structure- long straight chain -many hydrogen bonds to form adjacent chains called microfibils to bundle together to form macrofibils= rigid
Found in plants -insoluble -helixical for compact store -large no of alpha glucose molecules
Branched alpha glucose for large surface area-respiration liver and muscle tissues
Fatty acid
Long hydrocarbon + R-COOH
Single bond in fatty acid =
Saturated c-c bonds in r group
Double bond in fatty acid =
Unsaturated c=c bonds in r group
One glycerol and 3 fatty acids joined by condensation 3x H20 IS REMOVED
Phoshoplipid consist of
Two fatty acids,one glycerol and a phosphate group
Formation of phospholipid
The phospholipid molecule has a polar hydrophillic head (attracts water) containing the phosphate group and a non polar hydrophobic tail consisting of the fatty acid chains
What bonds do a primary structure have
-peptide bonds and first sequence of amino acids
Hydroylis of protein by
Heating or acid or enzyme
What is the secondary structure
Coling of the polypeptide chain as result of hydrogen bonds and peptide bonds. alpha helix and beta pleated sheet
Tertiary structure
Further foliding of the polypeptide chain due hydrogen bonds ,ionic and disulphide bridges eg fibrous proteins (kerartin- hair) globular (hormones/ enzymes)
Quaternary structure
A number of indivual polypetide chains eg antibodies or haemoglobin
An ions
Is an atom or group of atoms with an electric charge
Inorganic ion
Doesnt contain carbon so iron fe2+ and phosphate
What happens to between water molecules
Weak hydrogen bonds due to charges attracting it
Functions of water
Metabolic reaction (photosynthesis, digestion/hydroylsis) temperature regulation - specific latent heat of vapourisation solvent
Where is atp made
Respiration - energy
Function of atp
Energy storage molecule it stores it in high energy bonds between the phosphate groups
How does atp release energy
Hydrolysis to adp and pi by ATP hydrolyase
Atp is reformed by
Atp synthase eg photosynthesis
What is a habitat ?
A place where an organism lives
What is biodiversity?
The range of species found in a habitat
Species richness
The no of different species present in a community
What is a community ?
All the organisms of all the species that live in a habitat
Enzymes functions
Lock and Key theory
Active site is complimentary
Induced fit theory
The acitve site is not complimentary so it changes the active site
Endings of enymes and their meaning
Ase- carbohydrate - glycosidic bond ease-protein- peptide
Factors affecting rate of reaction
-enzyme concentration (run out substrates for es complexes) -substrate concentration increases so more es complexes then substrate conc is no longer the limiting factor ( max es complexes not enough enzymes) -temperature (kinetic energy increases so more collisions creating es complexes quicker until it reaches optimum temp and the max everything until it suceeds this then causes hydrogen/ionic bonds in enzyme to break Causes enzyme’s ts to change,so active s changes no longer compimentary) PH (ph changes cause hydrogen bonds to break in the specific tertiarty structure)
What is a competitive inhibitor ?
Inhhibitor competes with the substrate for the active site and binds preventing the substrate and active site binding so the rate of r is slower
Keywords for when an enzyme denatures.
Bonds break Tertiary structure Active site shape Not complementary No ES complexes
Enzyme denatures
Bonds break -hydrogen and ionic bonds in the enzyme break Tertiary structure - changes Active site shape -this causes the active site shape to change Not complementary -not complementary to active site So no ES complexes form
Difference between animal and plant cell
Plants cells have cell wall, starch grains and chloraplast and vacuole
Prokaryotic cells and eukaryotic cells differences
Pro= no membrane bound organelles -70s ribosomes - circular dna -plasmids -flagella
Function of the nucleus
Contains DNA which codes for proteins
Function of chloraplast
Carries out photosynthesis to produce glucose
Mitochondria function
Carries out aerobic respiration which releases energy in the form of ATP
Function of the smooth endoplasmic reticulum
Synthesises fats and transports fats around the cell
Rough endoplasmic reticulum FUNCTION
Protein synthesis and transports to golgi body
Function of the golgi body
To modify and package proteins producing vesicles and lysosomes
Lysosomes are
Digesting enzymes
Carry out protein synthesis
Steps of centrifugation
1. grind cell to break it 2. blend with a cold isotonic buffer solution 3. filter to remove cell debris 4. centrifuge spin 5.increases speed for next pellet
Roles of the cold isotonic buffer solution
Cold- prevents enzyme action isotonic - prevents osmosis buffer - maintains ph so no denaturing
The levels of pellets in a centrifuge
Nucleus Chloroplast Mitochondria endoplasmic ribosomes
A light microscope
-alive or dead organisms -2d -small cells thick or thin samples long wavelength of light so less resolution
Scanning electron microscope (ing-bouncING)
Electrons bounce dead thin samples 3d
Transmisson electron microscope
Electrons pass dead thin samples 2d
Levels of size of measurements
Mm -----> micrometres -----> nanometres x1000 ------------------------ x1000
Describe the digestion of starch
Starch enters the mouth and is hydrolysed into maltose by salivary amylase. In the duodenum it is again hydroylsed into maltose by pancreactic amylase which is breaking the glycosidic bonds . then in the ileum the maltose is hydrolysed by membrane bound maltase into alpha glucose
Describe the digestion of proteins
In the stomach the endopeptidase breaks the internal peptide bonds of the protein forming smaller polypeptide chains. In the duodenum the smaller polypeptide chains are hydrolysed by exo and endo peptidase to release amino acids and di peptides. therfore in the ileum membrane bound dipetidase hydrolysed the peptide bond of the dipeptide to form amino acids.
Digestion of lipids
The liver makes bile salts that is stored in the gallbladder . in the duodenum the bile salts emulsify these fats into smaller fats. pancreatic lipase hydrolyses ester bonds in lipids to form glycerol and fatty acids. In the ileum the membrane bound lipase hydrolyse the lipids further into 3 fatty acids and one glycerol and micelles
Absorption of glucose
The SODIUM POTASSIUM PUMP allows for sodium ions to be actively transported out of the cell , atp is required as it is against the concentration gradient . this lowers the sodium ion concentration inside the epithelial cell creating a conc gradient. 2. The glucose and sodium ions from the lumen bind to NA+/GLIUCOSE CO TRANSPORT PROTEINas they are facilitated diffused into the cell from (high-low ) 3. GLUCOSE CHANNEL PROTEIN allows glucose to be absorbed from the ep cell into the blood by facilitated diffusion
What do the proteins names change to when its proteins absorption
1. Na+/K pump 2. Na+/amino acid co transport protein 3. Amino acid channel protein
Absorption of fats
1. Micelles form - complex of bile salts , glycerol and fatty acids . Micelles bring glycerol and fatty acids to the cell membrane . glycerol and fatty acids diffused into cell across bilayer 2. ser synthesises to form lipids 2.5 golgi processes triglycerrides with a protein to form chylomicrons in a vesicle . vesicle realeases them so they can diffuse into lacteals. 3. fluid in lacteals drains into bloods
The structure of the ileum
Many long folds called villi . Thick smooth muscle layer , thin muscle layer end epithelium
What is the Villi
The villi are lined with a single layer of epithelial cells. Many small branching blood vessels called capillaries and long lymph vessels called a lacteal
Absorption of digestive products
Molecules move into the lumen , moves across microvilli of epithelial cells , moved across endothelial cells lining the capillary unit the blood
Cell membranes have a fluid mosaic. what is it?
The phospholipid layer is fluid because the phospholipids are always moving. the proteins are scattered in a mosaic pattern
Functions of the cell membrane
1. transport 2.digestion 3. immune responses
High to low concentration no energ req
Facilitated diffusion
Polar mols channel or carrier protein high to low
Active transport
Low to high so against conc g requires energy - atp carrier protein ( have specific binding site that the molecule joins too , changing shape of the binding site so the molecule can be transported ).
Co transport
2 mols transported together fd= high to low
Factors affection the rate of diffusion
- temp- kinetic energy - number of proteins -conc gradient -diffusion pathway distance -surface area
The netmovement of water from an area of high water potental to low
Describing transport keywords
1. Concentration gradient ( high to low / low to high (atp required ) 2. Transport protein ( channel or carrier ) 3.ATP require aka active transport
Phospholipid bilayer structure
Extrinsic . intrinsic proteins cholesterol
Reducing sugar
Benedicts solution and heat Red – Reducing sugar present Blue – Reducing sugar not present
Non reducing sugar
Do 1st test add an bendedicts and heat. ( reducing sugar) then add acid and heat to break the bonds add alkali (neutralise acid) add benedicts and heat Red –sugar present Blue – sugar not present
Test for starch
Add iodine to the substance a blue/black colour change should be observed
Test for protein
Add copper sulphate Add sodium hydroxide colour change to purple indicates present
What is antigen ?
Causes an immune response
What is a pathogen
A microorganisms that causes disease
The 4 types of cells
-memory t and B cell - Tc t killer cell -Th helper cell - B cell
What is the cellular response
Replication of t killer cells that detect antigens , that release perforating proteins which punch holes to cause the cell to break . The memory t and B cells remain
The humoral response
B cells activate and Replicate and make monoclonal antibodies . They agglutinate (glu =stops movement ) of the pathogen . They engulf and kill the pathogen by phagocytosis.