Topic 1 Bio Flashcards
Nitrate Ions
Amino acids - Proteins
Formation of DNA
Phosphate Ions
Formation of ATP,ADP, DNA, RNA
Chloride Ions
Needed in nerve impulses and many secretory systems
Hydrogen Carbonate Ions
Needed for buffering blood, won’t become acidic
Sodium Ions
Needed in nerve impulses and many secretory systems
Calcium Ions
Needed for formation of calcium pectate for the middle lamella between two cell walls in plants, and for bone formation and muscle contraction in animals
Hydrogen Ions
Needed in cellular respiration and photosynthesis, and in numerous pumps and systems in organisms as well as pH balance
Magnesium Ions
Needed for production of chlorophyll in plants
Water as a solvent
Polar solvent. Ionic and Covalently bonded substances dissolve. Most of chemical reactions in cells occur in water
Water as a transport medium
Substances dissolve and form colloids (floating in liquid) rather than solutions
Water max density and usefulness
At 4C. Useful because ice floats and provides an insulating layer. Ice melts quickly as one top. Means organisms can live in water in cold places
Water heat capacity
Very high so has a stable temperature.
water cant be compressed usefulness
Hydraulic mechanisms in organisms. Provide structure to cells
Cohesive water
Water molecules stick together. Useful for movement in plants.
Adhesive water
Water molecules are attracted to different molecules
Water surface tension
Due to cohesive nature, attraction between water is greater than to air so useful for pond skaters
Carbohydrates uses
Main energy source in human diet.
Also form an important part of the cell wall
Types of carbohydrates
Monosaccarides, disaccharides, polysaccharides
Monosaccarides info
Triose sugars
Pentose Sugars
Hexose Sugars
Simple sugars. with one oxygen and two hydrogen
Triose: Important in mitochondria where glucose is broken down into.
Pentose: Ribose and deoxyribose so important for genetic material
Hexose: taste sweet. glucose, galactose, fructose
A vs B Glucose
A - OH down
B - OH up
Dissacarides info
Two monosaccharides joined by condensation reaction so held together by glycosidic bond.
Sucrose, lactose, maltose
Polysaccharides (different types+info)
oligosaccharides are 3-10.
Storage molecules - very compact
Easily broken glycosidic bonds so rapid release.
Not soluble in water so no impact on water potential
Process to break glycosidic bonds
Hydrolysis
Starch is made of (describe each)
All alpha glucose
Amylose - straight chain. More compact. 1-4 bonds
and amylopectin - branched. 1-4,1-6 bonding
Why is pasta good for sport
Mix of amylose and amylopectin mean its broken down quick and slow for cellular respiration
What is glycogen
Carbohydrate found in animals. Important storage in fungi. Made up of alpha glucose
More 1,6 bonds than amylopectin so can be broken down very fast.
What is cellulose and what is special about its bonding
Important structural material in plants
Makes cell wall. Very strong
Long chains of beta glucose
Since beta the arrangement of hydrogen and OH means hydrogen bonds form leading to cross linking
Fats and oils characteristics
Fats are solid at room temp and oils are liquids. Lipids contain less Oxygen. Made up of fatty acids and glycerol which are attached with ester bonds
What is a fatty acid and types
Molecule with long chain and carboxycl group at end.
Can be saturated so no double bonds
Or saturated so multiple
How does a fat/oil form
one, two or three fatty acids attached to a glycerol
Lipids as an energy store
More energy dense than carbs
Properties of lipids and uses
Hydrophobic, waterproof organisms.
Good insulation, eg nerve impulses travelling faster
Insulate against heat loss
Low density, help animals float
Dissolve in organics but not in water so they dont interfere in cytoplasmic reaction
Phospholipid properties and use
Polar negative phosphate head (hydrophilic), glycerol with two hydrophobic fatty acid tails attached
forms a bilayer membrane
How many amino acids are there
About 20, each with different R group so different properties
Amino acid basic structure
Amino (-NH2), Carboxycl (-COOH) attached to a Carbon with an H.
4 ways amino acids bond and why
R Group.
Peptide bond is formed between amino and carboxyl group, when two amino acids form to form a dipeptide which then form a polypeptide chain.
Hydrogen bonding. Negative oxygen and positive amino. lots form in folding of chains
Disulphide bonds form covalently between cysteine molecules
Ionic bonding aren’t common but occur between amino acid side chains.
cysteine
amino acid used for formation of proteins
Primary Structure of a Protein
Linear sequence of amino acids in a peptide
Secondary Structure of a Protein and examples
arrangement of polypeptide chains into repeating structure with hydrogen bonding. Helix structure and fibrous proteins have mainly this
Tertiary Structure of protein and examples
3D organisation on top of secondary structure. Secondary is further folded.With hydrogen, sulphide and ionic bonds.
Globular proteins are example of tertiary structures.
Quaternary Structure of protein
Only in proteins with multiple polypeptide chains with the interactions between them
How does a protein get denatured
Change in pH or temperature permanently break the bonds that give a protein its 3D shape.
Collagen info
Gives strength to tendons, ligaments, bone and skin.
Most common structural protein in animals (35%)
High tensile strength
Made up of three polypeptide chains that form fibril and then a triple helix which is the fibre
Globular Proteins info
Complex tertiary and quaternary structures. Insoluble as they form colloids. Hold molecules in position in the cytoplasm.
Important for the immune system as antibodies are globular.
Conjugated proteins info and examples
When protein molecules are joined with a prosthetic group. Haemoglobin is example with its iron containing prosthetic group. Chlorophyll is another example.
Glycoproteins have a carbohydrate prosthetic
Lipoproteins have lipid prosthetic (LDL HDL cholesterol)
How to test for protein
Add Biuret reagent, goes from blue to purple in presence of protein
What are most common nucleotides made of and links to ATCGU
- Contains 5-carbon pentose sugars
- Either a purine base (with two nitrogen containing rings) or a pyrimidine base (with only one). Both are weak bases. A and G are purine and C,T,U are pyrimidine
- Phosphate group so they are acidic and carry negative charge
PHOSHATE HAS BASE ATTATCHED TO IT
How are nucleotides linked
Phosphodiester bonds between the sugar and phosphate groups on each nucleotide
How are two polynucleotide strands linked in DNA
A and T have two hydrogen bonds and C and G have three hydrogen bonds
5 prime vs 3 prime end
Number of carbon of the sugar the phosphate is attached to. (Clockwise)
Experimental evidence for semi-conservative replication of DNA vs conservative
Bacterial reproduction in heavier nitrogen vs lighter and should be no middle area (there was). Conservative would have two areas one heavy one light
How DNA replicates
1.DNA Helices unzips
2. DNA polymerase lines up and catalyses the linking of nucleotides along template strand
3. DNA ligase catalyses the formation of phosphodiester bonds between two strands of DNA
4. Automatically coil back up
Why is there triplet code,
To have enough combinations to code for all amino acids. Many code for the same amino acid so mutations have less catastrophic effects. Non-overrlapping so 3 only codes for 1 and degenerate
What is a gene
Sequence of bases on a DNA molecule coding for a specific sequence of amino acids
Why are non coding regions important
Regulate protein coding sequence
How mRNA forms
Transcription. RNA polymerase forms mRNA with phosphodiester bonds from DNA nucleotides free in the nucleus, coding against template strand of DNA. The small mRNA pass through the nuclear pores to the ribosome
How are proteins synthesised?
Translation. Ribosome moves along molecule of mRNA and binds amino acids together, peptide bonds form and then long chain and then protein forms after folding.
What is tRNA
tRNA is found in cytoplasm and has complex shape with anticodon. three bases on outside that corresponds to amino acid it has picked up on its binding side.
What is rRNA
Ribosomal RNA. Binds with proteins to form ribosomes
How to mass produce proteins
Polysomes. Groups of ribosomes joined by a single thread of mRNA. Ribosomes move along one after another producing many identical polypeptides.
What is a mutation
Pernament change in the DNA of an organism
Types of mutations
Point or gene mutation - single change, one base
Include substitutions, deletions and insertions
Chromosomal mutation: Changes in position of genes in the chromosome
Whole chromosome mutations: Entire chromosome is lost or duplicated
What causes more mutations
Mutagens - anything increasing the rate of mutations
Sickle cell disease
Sickle cell anaemia is when haemoglobin is a difference shape and cant carry oxygen well due to point mutation
What is a catalyst
Substance that changes rate of reaction without changing substances produced whilst being unaffected and used again.
Lowers activation energy
What are enzymes, what reactions do they facilitate, what types
Catalysts, globular proteins that show great specificity
Anabolic (Build up)
Catabolic (break down)
Intra and extra cellular
How do enzymes work (both models)
Enzyme substrate complex forms
Lock and key hypothesis is that active site has specific shape to each substrate, once the reaction is complete the substates change shape so don’t fit anymore
Induced fit hypothesis suggests that the active site is flexible. Binds around substrate to form active complex.
Two main types of reversible inhibition of enzymes. Describe
Competitive and non competitive
Competitive inhibition means something binds to the active site preventing substrate binding. Increase substate conc to overcome this
Non competitive inhibition means something binds elsewhere on the enzyme.
Irreversible inhibition of enzymes
Inhibitor binds with permanent covalent bonding. Occurs more slowly. Only used to kill people
End product inhibition of enzymes
Regulatory enzymes have a site where non competitive inhibition can occur. It is found at the beginning and is then inhibited by on of the end products in a metabolic pathway.
