Biology UNIT 1

?
What are properties of water?
-an important metabolite (substance in a metabolic reaction) used in condensation and hydrolysis reactions
-high heat capacity
-large latent heat of vaporisation (cooling effect with evaporation)
-strong cohesion between water molecules
1 of 57
What is a covalent bond?
-A covalent bond is a shared pair of electrons between two atoms
2 of 57
What makes water a polar molecule?
-Oxygen is more electronegative than hydrogen and therefore the electrons in the covalent bond are pulled more closely to the oxygen giving is a partially negative charge and hydrogen a partially positive charge.
3 of 57
Describe hydrogen bonds in water
-Individually weak however act as a collective force when in large numbers.
4 of 57
Describe hydrolysis and condensation
-Hydrolysis is when water is added across a bond to break it, this is called a hydrolysis reaction.
-Condensation is when water is removed from between two separate molecules.
5 of 57
Why is water having a high specific heat capacity useful?
Habitats of aquatic organisms have
6 of 57
Why is having cohesion and surface tension useful for water?
-Strong cohesion due to hydrogen bonding helps water to flow, for example travelling up columns in xylem.
-High surface tension when it comes into contact with air so sweat droplets will form.
7 of 57
Why is having a high latent heat of vaporisation useful in water?
-water evaporates when H bonds are broken but it takes a lot of energy to break these bonds (heat)
-when we sweat we lose heat evaporating the water cooling us down
8 of 57
Water as a solvent?
-Water is polar causing the slightly positively charged ends to attract negative ions and vice verse
-this means the ions will be surrounded by water and pulled apart (they dissolve)
9 of 57
What is capillary action?
-When water will rise up in a narrow vessel due to attraction to water molecules and the walls of the vessel and between the water molecules themselves.
10 of 57
What element do inorganic ions not contain?
Carbon
11 of 57
Why are iron ions (Fe^2+) important?
-They bind to oxygen and so are vital in haemoglobin.
-Aid in the transfer of electrons around the body
12 of 57
Why are hydrogen ions (H+) important?
-The conc_n of H+ ions in a solution determine the pH (more H+ = lower pH). Therefore the conc_n of these ions is important to enzyme activity.
13 of 57
Why are sodium ions (Na+) important?
-For the transport of glucose and amino acids around the body because glucose and amino acids can only pass through the cell membrane with sodium ions. This is co - transport.
14 of 57
Why are phosphate ions (PO4^3-) important?
-They condense together to form a phosphate group which are components in ATP, ADP, DNA and RNA.
15 of 57
What are monomers and polymers?
-Monomers are small units that form larger polymers.
-Polymers are large chains of monomers joined together.
16 of 57
What are all carbohydrates made out of?
-Carbon, hydrogen and oxygen.
17 of 57
What are monosaccharides? give 3 types.
-They are sweet tasting monomers from which larger carbohydrates are made from.
-Triose (C3H6O3), pentose (C5H10O5), Hexose (C6H12O6).
18 of 57
What are disaccharides? give three examples
-Formed from the condensation reaction between two monosaccharides to form a glycosidic bond leads to the formation of a disaccharide.
-Maltose (glucose+glucose), Sucrose (glucose+fructose), Lactose (glucose+galactose).
19 of 57
What are polysaccharides? give three examples
-Formed from many monosaccharide units.
-Starched (alpha glucose), Glycogen (alpha glucose), Cellulose (beta glucose)
20 of 57
What is starch?
-A polysaccharide that is found in plants
-Made from alpha glucose
-Important source of energy in the human diet
-Starch is hydrolysed by amylase to maltose which is then hydrolysed by maltase to (a) glucose.
21 of 57
What is glycogen?
-It is a storage of glucose found in the liver and muscle cells of animals
-It is highly branched.
22 of 57
What is cellulose and how is it used in plants?
-Linked chains of (b) glucose which caused the hydroxy groups to be inverted forming long and straight chains.
-Weak hydrogen bonds form in the chains and as the chain mesh together it gives a collective strength to the hydrogen bonds.
-Cellulose is used
23 of 57
Why are polysaccharides good storage molecules?
-They can compact to take up less cell space
-They are insoluble so cannot diffuse out of cells and do not affect water potential
-They are highly branched so there are more ends for enzymes to act on.
24 of 57
What are functions of lipids in organisms?
-Forms the phospholipid bilayer of cell membranes
-Insulation
-As an energy store
-Waterproofing
25 of 57
Why are lipids insoluble?
-Lipids are non polar due to their distribution of elections.
26 of 57
What is a triglyceride and what happens when it becomes unsaturated?
-Formed from one glycerol and 3 fatty acids
-It becomes unsaturated when a fatty acid chain has a carbon-carbon double bond. It caused a kink to form in the chain
-This causes the fatty acids to not be able to pact together which weakens the intermolecula
27 of 57
What are phospholipids and why are they useful in cell membranes?
-similar structure to triglyceride but with 2 fatty acids and a phosphate group
-The phosphate group (the head) is hydrophilic as it is negatively charged and attracts water
-The 2 fatty acid chains (the tail) are hydrophobic and so repel water.
28 of 57
What are proteins?
-they are polymers (polypeptides) made of amino acids.
29 of 57
What do all amino acids contain?
-carbon, nitrogen, hydrogen and oxygen.
-two amino acids also contain sulphur
30 of 57
Describe the structure of amino acids
-they have an acidic carboxyl group and an alkaline amino group.
-this causes them to resist change in pH (they can be used as buffers because of this).
31 of 57
What are dipeptides?
-Two amino acids linked together by a peptide bond via a condensation reaction.
32 of 57
What are polypeptides?
-Many amino acids joined by a peptide bond.
-In a cell this occurs in the ribosomes.
33 of 57
Describe the primary structure of proteins
-Amino acids are in a specific linear sequence in a polypeptide chain.
34 of 57
Describe the secondary structure of proteins
-The specific sequence of amino acids cause the chains to bend into a helix structure or into pleated sheets.
-Hydrogen bonds form.
35 of 57
Describe the tertiary structure of proteins
-The protein is folded into a unique 3D shape.
-It is held together by hydrogen and ionic bonds along with disulphide bridges if sulphur is present in the amino acids.
-The unique shape allows it to interact with other molecules.
36 of 57
Describe the quaternary structure of proteins
-It is formed when two or more polypeptide chains interact with each other.
-Bonds form in the R groups of the different chains.
-Haemoglobin is an example of a quaternary structure due to it having 4 polypeptide chains.
37 of 57
What happens if a mutation in the sequence of amino acids in a polypeptide chain occurs?
-The sequence will change which will cause the outcome of the secondary and tertiary structure to change.
38 of 57
What is denaturing and how can it occur?
-When the 3D shape of a protein is damaged beyond repair and can no longer carry out its function.
-High temperatures can cause this (the hydrogen bonds break).
-Extremes in pH (the ionic bonds break).
39 of 57
What are enzymes?
-They are globular proteins with a specific tertiary structure.
-Enzymes are biological catalysts meaning they speed up the chemical reaction without making the activation energy higher.
40 of 57
How does the active site work?
-The substrate binds to the active site as they are complementary in shape to each other (meaning one enzyme is only specific to one substrate).
-When bound they create an enzyme substrate complex.
41 of 57
Explain the difference between the lock and key model and the induced fit model of enzymes
-The lock and key model suggests there is a unique active site that is complementary to a unique substrate. The active site does NOT change.
-The induced fit model suggests the active site changes shape slightly to allow the substrate to fit in easier. T
42 of 57
How does conc_n affect enzyme activity?
-Enzyme conc_n: if it is too high then the ROR will increase at first (more enzymes to form more ES complexes) but then will start to steady.
-Substrate conc_n: if it is too high then the ROR will increase as well but then will start to steady as the enzy
43 of 57
How does temperature affect enzyme activity?
-Lower temp means lower ROR -> enzymes do not have kinetic energy needed to collide with substrate to make ES complexes.
-Increase in temp increases ROR.
-If temp goes over the optimum the H+ bonds will break in the tertiary structure and the enzyme will
44 of 57
How does pH affect enzyme activity?
-If pH is too high then it will interfere with the charges on the amino acids in the active site causing a change in its shape.
-If the pH is too high it will break the ionic bonds in the tertiary structure and the enzyme will denature.
45 of 57
What are competitive inhibitors and how do they affect enzyme activity?
-They are similar shape to the substrate so they can fit in the active site which forms an enzyme inhibitor-complex -> blocks substrates temporarily so less ES complexes form -> ROR slowed.
46 of 57
What are non-competitive inhibitors and how do they affect enzyme activity?
-They bind to the allosteric site of the enzyme -> causes the entire enzyme to change shape -> active site no longer complementary to the substrate.
-ES complexes cannot form and so the ROR is decreased and slowed.
47 of 57
What are the bases in DNA and RNA?
-Adenine, Thymine, Guanine and Cytosine.
-In RNA Uracil is present instead of Thymine.
48 of 57
What is the structure and purpose of DNA and RNA?
-Polymers of nucleotides joined by a phosphodiester bond.
-They are important information carrying molecules. DNA holds the genetic information and the RNA transfers the genetic information from the DNA to the ribosomes.
49 of 57
Describe DNA.
-Double helix molecule with two polynucleotide chains held together by hydrogen bonds between specific complimentary base pairs.
-Deoxyribose sugar, ACGT bases, double stranded in a helix, large, located in the nucleus.
50 of 57
Describe RNA.
-Short polynucleotide chain.
-Type of RNA include mRNA (singular straight chain) and tRNA (one strand in a clover leaf).
-Ribose sugar, ACGU bases, single stranded, located in the cytoplasm and nucleus.
51 of 57
What is ATP?
-A single molecule of adenosine triphosphate (ATP) is a nucleotide derivative and is formed from ribose, adenine and 3 phosphate groups.
-The hydrolysis of ATP releases the energy needed by muscle cells in the body.
52 of 57
Describe the hydrolysis of ATP.
-Catalysed by ATP hydrolase.
-One phosphate (Pi) is hydrolysed off the ATP molecule.
-Produces ADP + Pi + energy
53 of 57
What is the hydrolysis of ATP required in?
-Muscle contractions.
-Building of macromolecules.
-Active Transport.
54 of 57
What cab the inorganic phosphate released by the hydrolysis of ATP be used for?
-Can be used to phosphorylate other compounds which makes them more reactive (e.g. glucose phosphorylated into glucose phosphate in glycolysis).
55 of 57
How is ATP re-synthesised and what is an example of this occurring?
-Re-synthesised by a condensation reaction of ADP and pi, catalysed by ATP synthase.
-Happens during respiration and photosynthesis.
56 of 57
What makes ATP useful?
-Releases energy in small manageable amounts.
-Single step process.
-Immediate energy so energy is available rapidly.
-Phosphorylates other compounds.
-Lowers activation energy by phosphorylation.
-Can be re-synthesised.
57 of 57

Other cards in this set

Card 2

Front

What is a covalent bond?

Back

-A covalent bond is a shared pair of electrons between two atoms

Card 3

Front

What makes water a polar molecule?

Back

Preview of the front of card 3

Card 4

Front

Describe hydrogen bonds in water

Back

Preview of the front of card 4

Card 5

Front

Describe hydrolysis and condensation

Back

Preview of the front of card 5
View more cards

Comments

No comments have yet been made

Similar Biology resources:

Biology
Teacher recommended
See all Biology resources »See all Biological Molecules resources »