Biological Molecules Flashcards

Question

How the structure of triglycerides relate to their function?

Answer 1

-Used as energy store molecule. -Long hydrocarbon tails contains lots of chemical energy/insoluble, so they don't affect the water potential of the cell and cause water to enter the cell by osmosis. -Triglycerides clump together as insoluble droplets in the cells because the fatty acid tails are hydrophobic. The tails face inwards, shielding themselves from water with their glycerol heads. This means that they can be stored in cells as a source of energy without affecting the water potential.

Answer 2

-Make up the bilayer of the cell membranes -Heads are hydrophilic and tails are hydrophobic, so they form a double layer with their heads facing out towards the water -The centre of the bilayer is hydrophobic, water soluble substances can't easily pass through it- membrane acts as a barrier

Answer 3

-Its a test for lipids. -Shake the test substance with ethanol for a minute so it dissolves, then pour the solution into water. -Any lipid will show up as milky emulsion

Answer 4

Made up of one or more polypeptides (formed when more than two amino acids join together)

Answer 5

-Hydrogen bonds form -Makes it coil into an alpha helix or fold into a beta pleated sheet

Answer 6

-Final 3-D structure for proteins made from a single polypeptide chain. -Hydrogen bonds, ionic bonds and disulfide bridges form

Answer 7

-A test for proteins -Test solution needs to be alkaline- add sodium hydroxide solution -Then add some copper (II) sulfate solution -Purple= protein is present -If it stays blue no protein is present

Answer 8

-Roughly spherical due to the tight folding of the polypeptide chains -Soluble and have roles in metabolism (some help to break down large food molecules) (some help to synthesise large molecules) -Speed up chemical reactions by acting as biological catalysts. -Lower the activation energy of a reaction.

Answer 9

-Involved in the immune response -Made up of two light and two heavy polypeptide chain

Answer 10

-Present in cell membranes -Channel proteins contain hydrophilic and hydrophobic amino acids, which cause the protein to fold up and form a channel -Transport molecules and ions across membranes

Answer 11

-Physically strong -Consist of long polypeptide chains lying parallel to each other with cross-links between them. -Include keratin and collagen

Answer 12

-Temperature- increases the rate of reaction, more kinetic energy, molecules move faster, more likely to collide, energy of these collisions also increases, each collision is more likely to result in a reaction. -pH- Above and below the optimum pH, the H+ and OH- ions found in acids and alkalis can mess up the ionic bonds and hydrogen bonds. -Enzyme concentration- affects the rate of reaction Increasing the concentration of enzymes, increases the rate of reaction. However, if the amount of substrate is limited, adding more enzyme won't have any affects. -Substrate concentration- affects the rate of reaction to a point The higher the substrate concentration, the faster the reaction. Only true up to a 'saturation' point. All active sites are used, increase in conc of substrate wont have any effect.

Answer 13

-Competitive inhibitor have a similar shape to substrate molecules -They compete with the substrate molecules to bind to the active site, but no reaction takes place. -They block the active site, so no substrate can fit in.

Answer 14

-Bind to the enzyme away from its active site. -Causing active site to change shape so the substrate can no longer bind to it. -They don't 'compete' with the substrate because they are different shapes. -Increasing the concentration of substrate wont make any difference to the reaction rate.

Answer 15

How fast the product is made- -Catalase catalyses the breakdown of hydrogen peroxide into water and oxygen. We can measure how fast the product is made by measuring the volume of oxygen produced. -The oxygen released displaces the water from the measuring cylinder. 1-Set up boiling tubes containing the same volume and concentration of hydrogen peroxide. To keep the pH constant add equal volumes of a suitable buffer solution to each tube. 2-Set up the rest of the apparatus 3- Put each boiling tube in a water bath set to a different temperatures along with another tube containing catalase.. 4-Use a pipette to add the same volume and concentration of catalase to each tube. Then quickly attach the bung and delivery tube. 5-Record how much oxygen is released in the first minute 6-Repeat it at each temperature three times. Then find the average vol of oxygen produced 7- Calculate the average rate of reaction.

Answer 16

-Similar in structure to DNA. -Transfer genetic information from the DNA to ribosomes (synthesis protein)- ribosomes read the RNA to make polypeptides in a process called translation.

Answer 17

-A pentose sugar -A nitrogen containing organic base -A phosphate group

Answer 18

-Join up by condensation reaction between the phosphate group of one nucleotide and sugar of another. -Forms a phosphodiester bond -Chain of sugars and phosphates is known as the sugar-phosphate backbone.

Answer 19

-made of two polynucleotide chains in a double helix structure -Two DNA polynucleotide strands join together by hydrogen boning between the bases (A-T C-G) -Two hydrogen bonds form between A and T -Three hydrogen bonds from between C and G -Two antiparallel polynucleotide strands twist to form the DNA double helix.

Answer 20

1) -The enzyme DNA helicase breaks the hydrogen bonds between bases on the two polynucleotide DNA strands. -Makes the helix unwind to form two single strands 2) -Each original single strand acts as a template for a new strand. -Complementary base pairing means that free-floating DNA nucleotides are attracted to their complementary exposed bases on each original template strand. 3) - Condensation reaction joins the nucleotides together- catalysed by the enzyme DNA polymerase. -Hydrogen bonds form between the bases 4) -Each new DNA contains one original strand and one new strand.

Answer 21

-Metabolite -High latent heat of vaporisation (requires a lot of energy to break the hydrogen bonds between water molecules, useful for living organisms, they can use water loss through evaporation to cool down) -Buffer changes in temperature (Hydrogen binds between the water molecules can absorb a lot of energy, high specific heat capacity, useful for living organisms because water doesn't experience rapid temperature changes. Makes it good habitat, temp is more stable under water, helping them to maintain a constant internal body temperature) -Good solvent (a lot of metabolic reactions are ionic, the ions will get surrounded by water molecules) -Strong cohesion between water molecules (Very cohesive because they're polar, helps water to flow, high surface tension when it comes into contact with air)