ESSAY Flashcards
How long should you spend on the essay?
NO LONGER than 45 mins
This includes planning & writing!
Do I need to write an introduction or a conclusion?
NO
Should I plan both essay titles?
YES.
This will help you decide which essay you can write about in the most detail.
Which topics can fit into (almost) EVERY essay title?
- Photosynthesis
- Respiration
- Protein synthesis/Control of gene expression
- Immunology
- Synapse
- Receptors & Homeostasis
Describe the light dependent reaction (6)
- Chlorophyll absorbs light energy & Excites electrons
- electrons removed (Oxidation of chlorophyll) via photoionisation;
- Electrons move along carriers/electron transport chain releasing energy (Series of REDOX reactions)
- Energy released (by electrons) used to form proton gradient;
- H+ ions move through ATP synthase;
- providing energy to join ADP and Pi to form ATP;
- Photolysis of water produces 2 protons, 2 electrons and ½ oxygen;
- NADP reduced by electrons / electrons and protons / hydrogen;
Describe the light independent reaction (6)
- Carbon dioxide combines/reacts with ribulose bisphosphate/RuBP;
- Produces two glycerate (3- )phosphate/GP using (enzyme) Rubisco;
- GP reduced to triose phosphate;
- Using reduced NADP;
- Using energy from ATP;
- Triose phosphate converted to glucose/hexose/RuBP/ribulose bisphosphate/named organic substance;
Explain why plants that have more chlorophyll will grow faster than plants with less chlorophyll.
- Have faster production of ATP and reduced NADP;
- (So) have faster / more light-independent reaction;
- (So) produce more sugars that can be used in respiration;
- (So) have more energy for growth;
- Have faster / more synthesis of new organic materials.
Describe the process of glycolysis. [4]
- Phosphorylation of glucose using ATP;
- Oxidation of triose phosphate to pyruvate;
- Net gain of ATP;
- NAD reduced;
Describe how oxidation takes place in glycolysis and in the Krebs cycle. [4]
- removal of hydrogen/dehydrogenation;
- by enzymes/dehydrogenases;
- H accepted by NAD/reduced NAD formed;
- in Krebs cycle, FAD (used as well);
Explain how the amount of ATP is increased by reactions occurring inside a mitochondrion. [6]
- oxidation of/removal of electrons and H+
- from pyruvate
- acetyl CoA / 6 carbon compound; (credit oxidative decarboxylation)
- substrate level production of ATP / ATP produced in Krebs cycle;
- production of reduced NAD / FAD (allow they take up hydrogen);
- in matrix of mitochondria;
- electrons fed into electron transport chain / used in oxidative
- (Electrons) pass along carriers/through electron transport chain/through series of redox reactions;
- Energy released;
- Protons move into intermembrane space;
- ADP/ADP + Pi;
- ATP synthase;
The mitochondria in muscles contain many cristae. Explain the advantage of this. [2]
- larger surface area for electron carrier system / MORE oxidative phosphorylation;
- provide MORE ATP / energy for contraction
Describe Transcription in Eukaryotes [5]
- Hydrogen bonds (between DNA bases) break;
- (Only) one DNA strand acts as a template;
- (Free) RNA nucleotides align by complementary base pairing;
- (In RNA) Uracil base pairs with adenine (on DNA) OR (In RNA) Uracil is used in place of thymine;
- RNA polymerase joins (adjacent RNA) nucleotides;
- (By) phosphodiester bonds (between adjacent nucleotides);
- Pre-mRNA is spliced (to form mRNA) OR Introns are removed (to form mRNA);
Describe Translation [5]
- (mRNA attaches) to ribosomes OR (mRNA attaches) to rough endoplasmic reticulum;
- (tRNA) anticodons (bind to) complementary (mRNA) codons;
- tRNA brings a specific amino acid;
- Amino acids join by peptide bonds via condensation reaction;
- (Amino acids join together) with the use of ATP;
- tRNA released (after amino acid joined to polypeptide);
- The ribosome moves along the mRNA to form the polypeptide;
A mutation in a gene coding for an enzyme
could lead to the production of a non-functional enzyme. Explain how [5]
- Change in base sequence (of DNA/gene);
- Change in amino acid sequence / primary structure (of enzyme);
- Change in hydrogen/ionic/ disulphide bonds;
- Change in the tertiary structure/active site (of enzyme);
- Substrate not complementary/cannot bind (to enzyme / active site) / no enzyme-substrate complexes form;
Eukaryotic cells produce and release proteins.
Outline the role of organelles in the production, transport and release of proteins from eukaryotic cells. [5]
- DNA in nucleus is code (for protein);
- Ribosomes/rough endoplasmic reticulum produce (protein);
- Mitochondria produce ATP (for protein synthesis);
4 Golgi apparatus package/modify; OR Carbohydrate added/glycoprotein produced by Golgi apparatus;
5 Vesicles transport OR Rough endoplasmic reticulum transports; - (Vesicles) fuse with cell(-surface) membrane;