Teaching block 1 Flashcards

Question

Aerobic respiration in animals + plants

Answer 1

Glucose + oxygen --> water + carbon dioxide (+2880 kJ) C6H12O6 + 6O2 --> 6H20 + 6CO2

Answer 2

Glucose --> lactic acid (+150kJ) C6H12O6 --> 2CH3CH (OH) COO4

Answer 3

Glucose --> ethanol + carbon dioxide (+210 kJ) C6H12O6 --> 2CH3CH2OH + 2CO2

Answer 4

- to convert energy in glucose into energy in the ATP molecule - = providing energy for cells to function properly by driving cell’s biological processes.

Answer 5

**Structure**: - Rod-shaped organelles - Matrix – fluid - Cristae – folding of inner membrane - Outer membrane - Granules on cristae = ATP synthase **Function**: - Generation of chemical energy needed to power cell’s biochemical reaction = stored in adenosine triphosphate (ATP) molecule - The biochemical processes are known as cellular respiration - Through: Glycolysis --> Krebs cycle --> Electron transport chain (ETC) in oxidative phosphorylation

Answer 6

- Is a vesicle (small membrane enclosed space) that contains digestive enzymes. ‘suicide bags’ Functions: - Digestion of cellular waste + old organelles - Programmed cell death - destroy whole cells in programmed cell death (apoptosis) - Phagocytosis - digest bacteria phagocytosed by white blood cells (leucocytes)

Answer 7

1. Phagocytosis - cell feeding - uptake of small molecules and extracellular fluids by a cell through the formation of small vesicles 2. Pinocytosis - cell drinking - uptake of large particles, such as cell debris and microorganisms, by a cell through the formation of large vesicles

Answer 8

White blood cells engulfs bacterium = bacterium stored in vacuole --> lysosomes release digestive enzymes to digest bacterium - a white blood cell can digest about 12 bacteria then it dies --> lots of white blood cells = puss

Answer 9

Endo – inside Symbiosis (mutualism) – where 2 organisms live closely together + both benefit - Phagocytosis explains some of the theory of endosymbiosis – if an aerobic respiring bacterium is engulfed it could over evolutionary time become a mitochondrion + if a cyanobacterium was engulfed it could become a chloroplast - Chloroplasts + mitochondria are believed to have been free living bacteria which were phagocytosed / engulfed into a larger cell, but did not get digested. This became a mutualistic or symbiotic relationship - Theory of endosymbiosis first describes by Lynn Margolis

Answer 10

* Chloroplasts + mitochondria are about the same size as prokaryotes * Chloroplasts + mitochondria have a double membrane – so outer membrane believed to have been the vacuole + the inner membrane was the membrane of the bacterium * Ribosomes in chloroplasts and mitochondria are 70 S and in bacteria also 70 S, but 80 S in eukaryotes * Similar DNA - genetic sequencing has shown * Mitochondria + chloroplasts reproduce by binary fission which is how bacteria reproduce

Answer 11

- Are difficult to see with a light microscope so are sometimes called a ‘brush border’ - microscopic, finger-like projections on the surface of cells that increase the surface area for absorption or secretion - eg for absorption of digested food in the small intestines 1mm2 of intestines lining has 200 000 000 microvilli

Answer 12

- tiny hair-like structures that extend from the surface of cells - used in movement

Answer 13

- cells lining the human respiratory system have cilia (cilliated epithelial cells) - they are all covered in mucus which helps trap bacteria + pathogen = cilia move this material along the trachea to the pharynx (throat), where it can be swallowed or coughed up - Paramecium (type of single celled Protozoan) - fresh water unicellular organisms which are covered in cilia for swimming

Answer 14

- hair-like structure - which helps cells move - Euglena – a freshwater organism, has 2 flagellums, used in swimming

Answer 15

do drawings for cilia + flagellum structure

Answer 16

- Both cilia + flagella have a 9+2 arrangment of microtubules - Microtubules made of protein called tubulin - 9 microtubules around the edge + 2 in the centre - cells normally have one or two flagella or LOTS of cilia = can tell if its cilia if there are lots / its flagella if there are only a few

Answer 17

- cyclindrical organelles made of protein tubulin - 2 centrioles per cell - Used in cell division in spindle formation (mitosis + meiosis) - Also involved in the formation of cilia + flagella

Answer 18

- cyclindrical organelles made of protein tubulin - 2 centrioles per cell - similiar structure to cilia + flagella but without the central microtubules + are arranged in groups of 3 microtubules around the edge of structure - Centrosome = structure made of a pair of a pair of centrioles surrounded by a mass of material

Answer 19

- made of cellulose (fibre in human diet) - prevents plant cell from bursting

Answer 20

- Middle lamella = layer of 'glue' mad of calcium + magnesium pectates, that hold adjacent cells together - Plasmodesmata = a hole through the cell walls. cytoplasm, cell membrane + some organelles (eg smooth ER) can go through these holes

Answer 21

- converting light energy into energy in a glucose molecule - occurs in the chloroplast - Carbon dioxide + water (+sunlight to chlorophyll) --> glucose + oxygen - 6CO2 + 6H2O --> C6H12O6 + 6O2

Answer 22

Extracting / isolating a sample of a particular organelle, so you can research the biochemistry of the organelle

Answer 23

1. Put tissue into ice cold, isotonic buffer 2. Cut tissue into small pieces 3. Put tissue into blender/homogeniser to break up cells 4. Filter to remove debris (waste) 5. Centrifuge – organelles separate out in a particular order due to their density + shape 6. When taking test tube out of centrifuge have a solid pellet (containing specific organelle) at the bottom + a liquid supernatant above 7. Take out supernatant and centrifuge again to get other organelles [Supernatant = a liquid – it may contain organelle that need to be re-spun in a centrifuge]

Answer 24

- **Low temperature**- slows chemical reactions, preventing self-digestion by enzymes - **Isotonic** - means same water potential = prevents osmosis so organelles do not gain or lose water causing them to shrivel up or burst - **Buffer** - prevents pH change

Answer 25

1. Nuclei - 800 – 1000g [5-10min] 2. Mitochondria - 10000 - 20000g [15 - 20 min] 3. Lysosomes 4. Rough ER - 50000 – 80000g [30-50 min] 5. Plasma membrane - 80000 – 100000 [60 min] 6. Smooth ER 7. Free ribosomes - 150000 – 300000 [>60]

Answer 26

- smallest cells are 0-1nm -10μm - So small they don't need a transport system as they can use diffusion - There are lots of them: 1g of soil contains 100 million bacteria 10cm3 of milk (fresh) have 3000 million bacteria - Important in regulating through decay -They can fix nitrogen by converting atmospheric nitrogen into a form plants can use (nitrogen-fixing bacteria)

Answer 27

- capsule - peptidoglycan cell wall - Flagella - Pilus (pili) - Plasmid - nucleoid [chromosomes] - Fibriae - Mesosome - Cell membrane - 70s ribosomes

Answer 28

1. **Capsules** protection for cell, including protection from phagocytosis + prevents drying out [capsulated pneumococcal grow in humans causing pneumonia whereas non-capsulate strains are easily destroyed by phagocytic] 2. **Cell wall** made of peptidoglycan or murein (2 diff words for same thing)= cell wall prevents bursting 3. **Mesosome** – for respiration – artifact of electron microscope preparation [cell division, increase SA for aerobic respiration, DNA replication]

Answer 29

4. **Flagella** – cell movement - made of proteins called flagellin – no 9+2 arrangement no microtubule. Instead, it rotates. only place in nature where you get a wheel 5. **Pili** (singular pilus) or **fimbria** make cells sticky + are involved in cell to cell surface contact. - F-pilus is allows DNA to move from 1 bacterial cell to another in sexual reproduction

Answer 30

1. **Size** Prokaryotes - 0.5 - 5 um Eukaryotes - up to 40 um 2. **Form** Prokaryotes - Unicellular / filamentous Eukaryotes - Unicellulat/ filamentous/ multicellular 3. **Ribosome size** Prokaryotes - 70S Eukaryotes - 80S 4. **Endoplasmic reticulum** Prokaryotes - Not present Eukaryotes -Present 5. **Organelles** Prokaryotes - Few, no double membrane Eukaryotes -Many + some with double membrane

Answer 31

6. **Cell walls** Prokaryotes - Yes: peptidoglycan / murein Eukaryotes - Plant cell: cellulose 7. **Flagella** Prokaryotes - Yes but no microtubules + have flagellin Eukaryotes - Yes but 9+2 arrangment of microtubules 8. **Respiration** Prokaryotes - Uses mesosomes Eukaryotes - Use mitochondria 9. **Photosynthesis** Prokaryotes - Uses photosynthetic membranes not chloroplast Eukaryotes - Use chloroplast 10. **Nitrogen Fixing** Prokaryotes - Some bacteria can fix nitrogen Eukaryotes - No eukaryotes can fix nitrogen

Answer 32

- First discovered in 1890s by Russain scientist Ivanovski - He discovered a disease causing 'thing/agent/microbe' that could pass through a filter that was capable of stopping/trapping bacteria - Viruses are very small- about 10-300 nm - one virus = a virion

Answer 33

Bacterio - bacterium Phage - other word for virus - Bacteriophage is a virus that can infect a bacterium - They are useful in industrial genetic engineering as they can be used to inject DNA into a bacterium

Answer 34

1. Phage attaches to the cell wall of bacterium (host) 2. Digestion of bacterial host cell wall 3. Analogous (similar in function but different in structure) to a very thin hypodermic syringe - Bacteriophage's tail contracts + tail core passes through digested cell wall + DNA is injected into host bacterium

Answer 35

1. Bacteriophage attaches + Adsorption occurs, triggering the release of DNA into bacterium 2. phage (virus) DNA replicates 3. New virus heads appear 4. New completed phages (viruses) assembled 5. Lysis – bacterial cell bursts = releasing viruses which infect more bacteria

Answer 36

- Some prokaryotes can fix nitrogen + live in the root nodules of legumes (peas + beans) - legumes are eukaryote = example of a symbiotic / mutualistic relationship = the plant + the bacteria benefit [ plants get nitrogen + bacteria get sugars/place to live from plant + humans get nitrogen from plants essential for amino acids/proteins as there is nitrogen in all amino acid molecules ] - Nitrogen fixing bacteria are very important for human nutrition as we need nitrogen to make protein - bacteria are often very beneficial organisms + not something to be seen as bad and therefore need to be killed

Answer 37

- Bacteria fix nitrogen (1 mark) - symbiosis/mutualism (1 mark) - plants get nitrogen (1 mark) - bacteria get sugars/place to live from plant (1 mark) - humans get nitrogen from plants essential for amino acids / proteins as there is nitrogen in all amino acid molecules (1 mark) Extra mark for correct use of the word legume or knowing these include peans + beans

Answer 38

**Influenza** (flu) --> coughs + sneezes (droplets) --> Influenza virus A or B **Common cold** --> coughs + sneezes (droplets) --> Rhinovirus **Yellow fever** --> Mosquitos --> Togavirus B **Winter vomiting bug** --> virus contaminated surfaces + food --> Norovirus

Answer 39

``` hydrophilic head - water 'loving' hydrophobic tail - water 'hating' ``` - Phospholipid bilayer - 2 layers of phospholipid molecules - Membranes are about 7-10 nm thick - There are proteins (carrier/channel) + glycoproteins (cell signaling) between phospholipids in the bilayer

Answer 40

- Phospholipids are a barrier separating the outside + inside of the cell - with phospholipid **heads** facing the water in the cytoplasm or outside the cell - The **tails** are keeping away from water by all facing inwards. - **Protein** molecules can be receptors, ion channels, active transport, enzyme, electron carrier systems, carrier proteins - **Cholesterol** controls membrane fluidity - **Glycoproteins** – combination of a carbohydrate + a protein = example would be an antigen - **Antigen** used for cell recognition - antibodies produced in response to foreign antigens

Answer 41

- Called a fluid mosaic model because molecules in membrane can move (useful for cell during cell division so daughter cells get some of all types of membrane molecules) - Called a mosaic because it looks like a mosaic floor

Answer 42

- Passive immunity is when you are given ready-made antibodies - Active immunity is when you are given a weakened form of the disease so you learn how to produce antibodies for the future

Answer 43

**Solid** – atoms or molecules close together in a fixed regular structure **Liquid** – atoms or molecules close together, but can move around each other **Gas** – atoms or molecules quite a long way apart, moving around at high speed, colliding with each other

Answer 44

Solute is dissolved in a solvent to make a solution - **Solute** – solid - **Solvent** – a liquid. In biology solvents are usually water – used to dissolve a solute. - **Solution** – mixture of the solid and solvent. Sodium chloride (solute) + water (solvent) --> sodium chloride solution

Answer 45

- The movement of particles (molecules) from a place where they are in a high conc to a place where they are in a low conc due to the random movement of molecules - Diffusion evens out the distribution of molecules. - Diffusion occurs in a liquid and a gas. - Diffusion is faster in a gas than liquid (Leaves have air space in their spongy mesophyll because diffusion in gases is quicker than in the cytoplasm)

Answer 46

Brownian motion = looking at smoke particles floating in air using a microscope - The smoke particles move in a zig-zag pattern - The zig-zags are caused by air molecules colliding with the smoke particles = causing them to move + change direction - =shows how air molecules have a random movement

Answer 47

process by which water molecules move through a semipermeable membrane from an area of high water concentration to an area of low water concentration

Answer 48

- These all mean the same thing for osmosis] - A membrane with small holes (aquaporins) - Water molecules are small = can go through holes - Sucrose molecules (sugar) are large = cannot go through holes

Answer 49

``` 1. Animal cell in water ``` - water enters cell (osmosis) from area of low solute conc to area of high solute conc through semi-permeable membrane - cell bursts = **cell lysis** ``` 2. Animal cell in concentrated salt solution ``` - water leaves the cell (low solute conc to high solute conc) - = **cell shrivells up**

Answer 50

``` 1. Plant cell in water ``` - **Cell is turgid**, has a high turgor pressure - = Cell membrane pushed against cell wall - Cell wall prevents bursting ``` 2. Plant cell in 1M sucrose Solution ``` - Water leaves the cell - cell membrane separates from cell wall = cell is said to be plasmolysed - =cell has low turgor pressure = **cell is flaccid**

Answer 51

- Incipient plasmolysis is when cell membrane is just starting to pull away from cell wall - Happens when concentration inside the cytoplasm + outside is about the same - = so **water enters + leaves at the same rate** - = No net movement of water molecules = movement of water in + out is in equilibrium

Answer 52

- Jam – contains lots of sugar so water leaves bacterial cells and bacteria cannot destroy the jam. - Salt – food preservation - Salt – infection control – rub salt into a wound - In grown toenail - Plants exposed to salt – live near the sea – thick waxy cuticles and thick fleshy leaves. Wax reduces water loss and thick fleshy leaves reduces the surface area to reduce water loss. - Water uptake into plant roots is by osmosis. - Opening + closing of stomata uses osmosis. - Osmoregulation – excretory system – patient hydration

Answer 53

A saltmarsh is a low lying area of vegetation on the coast, which is flooded by the sea up to twice per day The amount of flooding depending on the height of the tides which in turn depends on the position of the sun + moon

Answer 54

Saltmarsh plants have to get water from the salty mud they are growing in as well as resist water loss from leaves which can be submerged in seawater twice per day = Consequently these plants have thick fleshy leaves (low surface area) with a waterproof waxy cuticle.

Answer 55

- Water potential = ψw Pronounced Psi - Is a measure of pressure using units Pascals (Pa) or kPa - Water molecules exert pressure - Pure water has the maximum water potential which is 0 Pa - All solutions have lower water potentials than pure water, so negative values for water potential - Water always moves from a region of high water potential to low water potential **Osmosis is the movement of water molecules from a region of higher water potential to a region of lower water potential through a semi-permeable membrane**

Answer 56

- The movement of molecules through a membrane + against a concentration gradient - Requires an input of energy, which usually comes from ATP (adenosine triphosphate). - Uses membrane carrier proteins

Answer 57

- Absorption of amino acids from intestine into the blood. - Reabsorption of glucose in kidney (first convoluted tubule). - Sodium – potassium pump in nerves( exchange of Na+ + K+ to allow electrical conducting) ``` A way to check whether active transport is involved is to add a respiratory poison (eg cyanide) Cyanide prevents respiration and therefore prevents ATP production. If transport is stopped with cyanide then it is active transport. ```

Answer 58

- Carrier molecule binds to + hydrolyses ATP - making a 'high energy' complex - H+ ions binds to + combine with the 'high energy' complex - ATP attaches to carrier protein releasing energy and then ADP released - The energy causes the carrier protein to change shape, pumping the hydrogen ion through the membrane - Hydrogen ion released + carrier protein returns to original shape - The shape (conformation) change lowers affinity of carrier for H+. phosphat is lost + this induces another shape change back to original in step 1

Answer 59

- tiny pores, mostly located on the underside of leaves - that facilitate gas exchange between the plant + the environment - They control the entry of CO2 for photosynthesis + the exit of O2 + water vapor (transpiration) - stomata is surrounded by guard cells and lower epidermis cells

Answer 60

- Diffusion, but involves large protein molecules - Passive process that moves molecules across a cell membrane from high to low concentration with using proteins - Two types = carrier proteins + ion channels

Answer 61

- carrier protein is within the phospholipid bilayer - Protein open from one side of membrane where conc is higher = molecule enters it = protein closes from that side and opens on other side = molecule exits on other side where conc is lower - movement down conc gradient - No input of energy - lets water molecules or small ions through quickly

Answer 62

- stimulus causes the "gate" to open or shut. - for diffusion of charged ions: Ca2+, Na+, K+, Cl- - Ions do not move easily through the non-polar lipid bilayer - One million ions per second can go through one ion channel - A gated ion channel is an ion channel that can open + close

Answer 63

**Proteins are polymers of amino acids, formed by long chains of amino acids joined together by peptide bond** - Only 20 amino acids are found in organisms.

Answer 64

1. **Structural proteins** - Keratin – hair - Collagen – tendons - Actin and myosis – muscles - Elastin - ligaments 2. **Transport** - Transport across membranes (ion channels etc) - Haemoglobin in transporting oxygen 3. **Enzymes** - Digestive enzymes - Enzymes involved in metabolism 4. **Hormones** - Protein hormones - eg Insulin - (some hormones are made from steroids such as testosterone = not protein) 5. **Antibodies** - Defense against diseases - eg antibodies for covid-19

Answer 65

- **Glycoprotein** = combination of protein + carbohydrates (eg mucus) - **Lipoprotein** = combination of a protein + a lipid - **Metalloprotein** = combination of a metal + a protein (eg haemoglobin, which contains iron)

Answer 66

- contain **Amino group** (NH3) - Contain **carboxylic acid group** (COOH) - contain **R group** or seen as 'H' - Amino acids are different from each other because they have a different R-group - EG: A single hydrogen in the R-group = is glycine - EG: CH3 in the R-group = Alanine

Answer 67

answer it is not very clear - A short chain of amino acids is a polypeptide - whereas a long or folded chain or two or more chains of amino acids is a protein

Answer 68

- Two amino acids bond together to make a **dipeptide** - Water is released so this is a **condensation reaction** - The bond formed is called a **peptide bond** (forms between a NH2 + COOH group - There is still an amino acid at one end + a carboxylic acid group at the other end so the molecule can continue to grow in length

Answer 69

- **Dipeptide** = two amino acids bonded together by a peptide bond. - **Tripeptide** = three amino acids bonded together by peptide bonds. - **Polypeptide** = a chain of amino acids up to about 50 amino acids. A polypeptide is a protein, but many proteins (e.g. insulin) are far too large and complex to be called polypeptides.

Answer 70

- light travels as a wave **Unpolarised light** - the electric field vectors are randomly oriented - = causing vibrations in multiple directions (sunlight, incandescent bulbs, halogen lighting) - Light waves that reflect in more than one place/direction **Polarised light** - The electric field vectors are aligned in a single plane - = resulting in vibrations in one direction (A laser) - polarized light waves are those that reflect in a single place/direction - - shine a beam of light (unpolarised) through a polarizer (polarising filter) = light becomes polarised - Polarising sunglasses completely cut out reflections = because reflected light is also polarised

Answer 71

- **Dextrorotation** = rotating polarised light to the right (clockwise) -EG D-alanine - **Laevorotation** (/ levorotation) = rotating polarised light to the left (counterclockwise) -EG L-alanine.

Answer 72

Central carbon bonded to four different groups. Asymetric. - Stereoisomers of amino acids are non-superimposable mirror images of each other that exhibit optical isomerism

Answer 73

All amino acids except glycine have stereoisomers, which are compounds that exist in two forms: L-and D- - The **L-form** (Laevo) is left-handed - The **D-form** (Dextro) is right-handed - EG L-alanine has the CH3 on the left side + NH2 on the right side, but D-alanine has the CH3 on the right side + NH2 on the left side (both have COOH at the top and H at the bottom, with a central C) | see drawing

Answer 74

1 - 14 ``` 1- strong acid 3 - 6 - weak acid ``` ```7- neutral``` ``` 8 - 13 - weak alkali 14 - strong alkali ```

Answer 75

**logarithmic** ph scale = - for ech 1 pH change towards 1 = there is10x the amount of hydrogen present as the pH before that eg if there were 20 hydrogens at pH 5, then at pH 4 there will be 200 hydrogens.

Answer 76

- Increased carbon dioxide in the atmosphere dissolves in seawater to create carbonic acid - = This reduces availability of calcium carbonate making it difficult for organisms (eg corals + molluscs) to incorporate calcium carbonate into their shells - coral growth is already slowing = suggest will stop by the year 2035 + corals start to dissolve by 2060

Answer 77

- at low pH, the amino acid has more hydrogens - A zwitterion is a molecule with an equal number of positively and negatively charged functional groups - amino acid common example - Amino acids act as buffers (a chemical that prevents / reduces pH change) - as pH changes structure of amino acid, it will also change structure of protein - enzymes are sensitive to pH

Answer 78

- S-S bonds - They are covalent links between the Sulphur atoms of two cysteine amino acids - Can only be formed between 2 cysteine molecules as these are the only amino acids containing sulphur - important for the stability + proper folding of proteins in tertiary structure - Disulphide bridges are found in insulin.

Answer 79

- disulphide bridge hold the 2 chains (A chain + B chain ) together in an insulin molecule - A chain- 21 amino acids = 5 amino acids, 2 cysteine, 8 amino acids, cysteine, amino acid - B chain- 30 = 6 amino acids, cysteine, 11 amino acids, cysteine, 11 amino acids

Answer 80

- **water**: Hydrogen bonds are very important because they mean water is a liquid at the temperature range at which biomolecules function. Forms between partial negative O- and partial positive H+

Answer 81

- **Protein**: H bonds form between 2 polypeptides (or parts of the same polypeptide or protein) - Hydrogen bond between the δ+ H from NH2 and the δ- O from COOH of another amino acid - **Amino acid**: Hydrogen bonds can hold a chain of amino acids together in a helix. - EG- Keratin is a protein found in hair + the helical structure combined with hydrogen bonds makes hair stretchy

Answer 82

**Primary structure** = the order / sequence of amino acids in a protein. **Secondary structure** = Folding of protein into alpha helix (in keratin) or beta pleated sheet **Tertiary structure** = the 3D shape of a protein results from bonds between distant parts of a chain = causing the chain to fold. **Quaternary structure** = the relative positioning of two or more polypeptide chains associated in one protein. There is no covalent bonding between these chains??. Held together by hydrogen bonds, van der Waals bonds, london dispersion forces, disulphide bridges, electrostatic forces

Answer 83

- Chromosomes are normally in pairs. - A **human body cell** has 23 pairs of homologous chromosomes = **46** chromosomes = **diploid number** (2n) - **Gametes** have half this number of chromosomes = are **haploid** (n) = **23** = chromosomes in gamete are not in pairs - A gamete must have half the normal diploid number, so that fertilisation results in the zygote having the normal diploid number of chromosomes. **Fertilisation > 23 + 23 = 46** Sperm + Egg = Zygote Gametes = sperm + eggs. Zygote = fertilised egg

Answer 84

A) Interphase B) Early prophase C) Late prophase D) Early metaphase E) Late metaphase F) Early anaphase G) Late anaphase H) Early telophase I) Late telophase

Answer 85

**A) Interphase** - cell has normal appearance of non-dividing cell condition: chromosomes too threadlike for clear visibility - cell grows + prepares for division by replicating its DNA + organelles **B) Early prophase** - Chromosomes become visible as they contract + nucleulos shrinks - centrioles at opposite sides of the nucleus - spindle fibres start to form **C) Late prophase** - Chromosomes become shorter + fatter - each seen to consist of a pair chromatids joined at the centromere - Nucleolus disappears - Prophase ends with breakdown of nucleus membrane

Answer 86

**D) Early metaphase** - Chromosomes arrange themselves on equator of spindle - homologous chromosomes do not associate **E) Late metaphase** - Chromatids draw apart at the centromere region - the chromatids of each chromosome are orientated towards opposite poles of the spindle

Answer 87

**F) Early anaphase** - Chromatids part company + migrate to opposite poles of cell - he centromeres leading **G) Late anaphase** - Chromosomes reach their destination on opposite poles

Answer 88

**H) Early telophase** - The cell starts to constrict across the middle **I) Late telophase** - Constriction continues - Nucleur membrane + nucleolus reformed in each daughter cell - spindle apparatus degenerates - Chromosomes eventually regain their threadlike form + the cells return to resting condition (interphase) - the diploid daughter cells are idntical to original parents cell (have precisely the same chromosome constitution)

Answer 89

A) Interphase B) Early prophase 1 C) Mid prophase 1 D) Late prophase 1 E) Metaphase 1 F) Anaphase 1 G) Telophase 1 H) Prophase 2 I) Metaphase 2 J) Anaphase 2 K) Telophase 2

Answer 90

**A) Interphase** - Cell in normal non-dividing conditions with chromosomes long + threadlike **B) Early prophase 1** - Chromosomes contract, becoming more clearly visible - Nucleolus shrinks **C) Mid prophase 1** - Homologous chromosomes come together (synapsis) forming a bivalent **D) Late prophase 1** - Each chromosome seem to consist of a pair of chromatids

Answer 91

**E) Metaphase 1** - Chromosomes arrange themselves on equator of spindle **F) Anaphase 1** - Homologous chromosomes part company + migrate to opposite poles of the cell **G) Telophase 1** - The chromosomes have reached their destination + the cell constricts across middle (same as mitosis)

Answer 92

**H) Prophase 2** - The 2 daughter cells prepare for the second meitotic division: centrioles have replicated + a new spindle is formed **I) Metaphase 2** - Chromosomes arrange themselves on the spindle

Answer 93

**J) Anaphase 2** - Chromatids part company + migrate to opposite poles of the cell **K) Telophase 2** - Cell constricts across the middle + the nucleur membranes + nucleoli are reformes (same as end of mitosis) - Chromosomes regain their threadlike form + the cells go into the resting state (interphase) - the haploid daughter cells have half the number of chromosomes as the original parent cell

Answer 94

- biological catalysts - A catalysts - a chemical that speeds up a reaction without being used up. - They speed up reaction by providing alternative reaction pathway with lower activation energy - = catalyst can be used many times over a long period of time An example of a catalysts is the catalytic converter in a car exhaust system. It converts carbon monoxide to carbon dioxide, breaks down waste hydrocarbons + also reduces the emissions of nitrogen oxides.

Answer 95

Enzyme naming -usually named after the substrate with the latters 'ase' at the end Substrate --> Enzyme --> Products Starch --> **Amylase** --> maltose Maltose --> **Maltase** --> glucose Lipid --> **Lipase** --> Fatty acids + glycerol Proteins --> **pepsin / protease** --> polypeptides + amino acids Polypeptide --> **Trypsin** --> amino acids Hydrogen peroxide --> **Catalase** --> water + oxygen

Answer 96

- Enzymes are made from globular proteins. - Enzymes are denatured by high temperatures. - = greater than 40°C = part of the reason that human body temperature is 37°C. Body temperature is just below the temperature at which enzymes would be denatured. - Fever, heat stroke can put a human body temp above 37°C = is potentially dangerous

Answer 97

- Catalase found in yeast cells, potato + liver. - catalyses- Hydrogen peroxide --> oxygen + water 2H2O2 --> O2 + 2H2O - Catalase has one of the fastest turnover numbers known = 6000000 - Turnover number = number of molecules one molecule of enzyme will break down per minute.

Answer 98

1. test tube 1 - 1cm3 yeast suspension test tube 2 - 2cm3 hydrogen peroxide + washing liquid 2. Put test tubes in water bath for 5 minutes 3. then add hydrogen peroxide to yeast + Wait 30 seconds - = will produce froth = bubbles of oxygen (as O2 is a product) - = measure the 'froth height' - froth height is direclty proportional to rate of reaction

Answer 99

- Temperature quotient. Q10 = 2 - = between 0- optimum temp (=40°C for catalase) everytime temp increases by 10°C, the reaction rate doubles - until it reaches the optimum temp = after that ROR will drop to 0 as enzyme denatures

Answer 100

**Poikilotherms** - cold blooded organisms **homeotherms** - warm blooded organisms

Answer 101

- Enzymes have an optimum pH = the pH they work fastest at - extreme pH = denature = active site shape changed - Pepsin – found in the stomach where there is hydrochloric acid about pH 1-2. - Trypsin – found in the small intestine pH 8.5

Answer 102

- the number of substrate molecules that 1 molecule of enzymes convert into products pr minute - catalase is one of the fastest enzymes = turnover value of 6 million

Answer 103

- substrate binds to specific active site on enzyme (specifity - enzyme will only work on 1 substrate) - enzyme-substrate complex - enzyme catalyses reaction + converts it to products - enzyme is free to find another substrate molecule `INDUCED FIT MODEL - enzyme changes shape slightly to fit substrate`

Answer 104

- chemicals that slow/ stop an enzyme from working - can temporarily or permanently stop an enzyme from working -enzyme inhibitors may include poisons we've heard of... - arsenic - mercury - sulphonamine drugs - sarin - cyanide - curare

Answer 105

- doesn't bind permanently to active site - it **FLOATS** in an active site - it floats in + out of active site competing with substrates = slows the enzyme down but doesn't stop it working

Answer 106

- inhibitor molecule fits permanently into the **allosteric site** = this permanently changes the shape of the enzyme molecule =active site loses specific shape = doesn't work again since cant bind to substrate Allosteric site = a binding site on an enzyme that is separate from the active site

Answer 107

- One glycerol molcule bonded to 3 fatty acids - through ester bonds in condensation reaction - 3 molecules of water (H2O) are produced when ester linkage forms (glycerol molecule down the side is hydrocarbon chain but on the right side of it its -OH = the H from this O-H is what bonds with the OH from the COOH of the 3 fatty accids...dont have to draw whole carbon chain out for them just the carboxylic acid group bonded to -R1, R2, R3)

Answer 108

- both consist of a hydrocarbon chain with carboxylic acid on the end of the chain **Saturated**: - lipids which **dont contain any C=C double bonds** - = has full number of H atoms [found in animal fats] **Unsaturated**: - lipids which **contain C=C double bonds** in carbon chain - = it does not have the full number of hydrogen atoms [found in plants] - The double bond causes a bend in the carbon chain

Answer 109

Length of the carbon chain determines the **type of fatty acid**. Examples: 1. *Stearic acid*: CH3(CH2)16 COOH 2. *Palmitic acid*: CH3(CH2)14 COOH

Answer 110

- Found in cell membranes – fluid mosaic model - **Polar head** – contains a negatively charged phosphate group = hydrophilic (water loving) - **Non-polar tail** – is hydrophobic (water hating) fatty acids Phospholipid Molecular Structure = Carbon chains will be longer than shown + can contain double bonds, which form ‘kinks’. [SEARCH ON GOOGLE TO SEE STRUCTURE]

Answer 111

* carbon atoms labelled in clockwise * a glucose has H ontop and OH under * B glucose has OH ontop and H under

Answer 112

glucose + glucose –> maltose glucose + galactose –> lactose glucose + fructose –> sucrose

Answer 113

- **starch** - made of a-glucose (mix of 2 polysacharides: amylose + amylopectin) - **cellulose** - made of b-glucose = we cant digest - **glycogen** - a-glucose - food store in animals **starch** --> **maltose** (by amylase in mouth + dulodenum) --> **glucose** (maltase in ileum of small intestine) - starch is digested to reduce the molecule to a size that can pass through semi-permeable membrane - gut wall

Answer 114

A Tetrose - a **4** carbon monosacharide A Pentose - a **5** carbon monosacharide A Hexose - a **6** carbon monosacharide [glucose]

Answer 115

* glycosidic links/bonds form by glycosidic condensation between 2 chains of glucose molecules between C1 + C6 * The same type of reaction bonds glucose molecules into their chain between C1 + C4

Answer 116

A storage polysacharide in plants made of a amylose + amylopectin **Amylose** (approx 20%) - linear chain of a-glucose molecules joined by 1-4 glycosidic bonds (same as maltose) - adopts a helical structure due to the intramolecular arrangments of bonds in carbon **Amylopectin** (approx 80%) - chain of a-glucose molecules joined by 1-4 glycosidic bonds - with branching formed by 1-6 glycosidic bonds

Answer 117

main energy storage polysacharide in animals - Chain of **a-glucose** molecules joined by **1-4** glycosidic bonds - with branching formed by **1-6** glycosidic bonds - even **more branching** than amylopetin but same structure

Answer 118

Structural polysacharide in plants * linear chain of B-glucose joined by 1-4 glycosidic bonds * cellulose froms straight chains + is the basis of plant fibre

Teaching block 1 Flashcards

part 1 (143 cards)