National 4&5 Biology. Cells Topic Summary Notes. Learning Outcomes (National 5 learning outcomes in shaded box)

Transcription

1 National 4&5 Biology Cells Topic Summary Notes Learning Outcomes (National 5 learning outcomes in shaded box)

2 What you should know about CELL STRUCTURE 1 Label a typical animal cell with cell membrane, nucleus and cytoplasm 2 Label a typical animal cell with the structures in 1 and mitochondria & ribosomes. 3 Label a typical plant cell with cell wall, chloroplasts, cell membrane, vacuole, nucleus, cytoplasm. 4 Label a typical plant cell with the structures in 3 and mitochondria & ribosomes. 5 Label a typical fungal cell with cell wall, cell membrane, nucleus, cytoplasm. 6 Label a typical bacterial cell with cell wall, cell membrane, plasmids, DNA. 7 The functions of cell wall, chloroplasts, cell membrane, vacuole, nucleus, cytoplasm. 8 The functions of the structures in 7, and mitochondria & ribosomes. 9 The difference between a plant cell wall and fungal and bacterial cell walls. Properties of microorganisms and their use in industry 1 Why we use microorganisms in industry 2 3 How yeast is used in brewing and baking How bacteria are use in yoghurt making, cheese production and making biogas 2

3 What you should know about TRANSPORT ACROSS MEMBRANES 1 What the cell membrane is made of 2 What a concentration gradient is 3 The definition of diffusion 4 The importance of diffusion The definition of osmosis The effects of osmosis on plant cells using the terms turgid and plasmolysed. The effects of osmosis on animal cells using the terms burst and shrink The terms passive and active transport and know the energy requirement of each. What you should know about ENZYMES 1 The function of enzymes in cells The name of the substance the enzyme acts on and the name of the substance produced 2 What is meant by enzyme specificity 3 What a degradation reaction is and be able to give some examples 4 What a synthesis reaction is and be able to give some examples. 5 How enzyme activity is affected by temperature and ph. 3

4 7 What is meant by optimum conditions for an enzyme. 8 What happens when an enzyme is denatured 9 Know examples of industries which use enzymes 10 Know the name of the enzymes used in cheese making 11 Know three sources of rennet What you should know about RESPIRATION 1 State that the chemical energy stored in glucose is released by all cells through a series of enzyme-controlled reactions called respiration. 2 Explain that the energy released from the breakdown of glucose is used to generate ATP from ADP and phosphate. 3 The chemical energy stored in ATP can be released by breaking it down to ADP and phosphate. 4 What the energy stored in ATP is used for in the cell. 5 The name of the first stage of respiration and where in the cell it takes place. 7 What happens to glucose during the first stage of respiration 8 How many molecules of ATP are produced during the first stage of respiration. 9 Where stage 2 of aerobic respiration takes place 10 What is required for stage 2 to occur 11 The products of stage 2. 4

5 12 How many molecules of ATP (in total) are produced from one molecule of glucose during aerobic respiration. 13 In what conditions anaerobic respiration takes place. 14 The products of anaerobic respiration in animal cells. 15 The effect of lactic acid on muscles 16 Anaerobic respiration in animals is reversible. 17 The products of anaerobic respiration in plants and yeast, 18 Anaerobic respiration in plants and yeast is irreversible. 5

6 TYPICAL ANIMAL CELL TYPICAL PLANT CELL 6

7 TYPICAL BACTERIAL CELL TYPICAL FUNGAL CELL 7

8 Use the words from the word bank to label the diagrams and complete the table PART OF CELL FUNCTION Controls what enters and leaves the cell Liquid in the cell where the cells activities take place Controls the cells activities Gives the cell a fixed shape Where photosynthesis takes place A fluid filled space containing cell sap Where proteins are made Where energy is produced by respiration A circle of genetic material Plant cell walls contain. Bacterial and fungal cells do not. WORDBANK WORDS CAN BE USED MORE THAN ONCE Cell membrane cytoplasm nucleus Cell wall chloroplast vacuole mitochondrion ribosome plasmid Circular chromosome (DNA) cellulose 8

9 Transport across membranes Cell membranes contain and. The cell membrane is. This means that only, soluble molecules can pass through A CONCENTRATION GRADIENT is the difference in concentration between one side of the membrane and the other. If there is a big difference in then the concentration gradient is. If there is a small difference in concentration then the is low. DIFFUSION is the movement of molecules from an area of concentration to an area of concentration until the concentrations are equal. OSMOSIS is the movement of molecules from an area of water concentration to an area of water concentration across a membrane. 9

10 Osmosis in Animal Cells When placed in pure water, water the cell from an area of water concentration to an area of water concentration and the cell bursts. When placed in a high concentration of salt or sugar, water the cell from an areas of high concentration to an area of water concentration so the cell shrinks. Water cell. Cell. Water cell. Cell. Osmosis in Plant Cells Cells placed in strong salt or sugar solution When placed in pure water, the water the cell and the cell swells up. We say that the cell is TURGID. The stops the cell bursting. In a high concentration of salt or sugar the water the cell and the cell membrane shrinks away from the cell wall. We say that the cell is PLASMOLYSED. Water cell. Cell. Water cell. Cell. 10

11 WORDBANK WORDS CAN BE USED MORE THAN ONCE turgid plasmolysed leaves enters Cell wall water high low Selectively permeable Phospholipid small protein 11

12 Enzymes E.g ENZYMES are biological which up chemical reactions They are found in every living cell. Without, chemical reactions would happen too to support life. The substance an enzyme acts on is called a. The substance formed from the reaction is called the. C Hydrogen Peroxide + Each enzyme acts only on one substrate. The part of an enzyme where the catalytic activity takes place is called the. Only the specific substrate can fit into these sites. 12

13 There are 2 types of enzyme reaction: 1. DEGRADATION REACTIONS - The substrate is into smaller products 2. SYNTHESIS REACTIONS - Substrate molecules are into larger molecules. REACTION REACTION + + ENZYME SUBSTRATE ENZYME- SUBSTRATE COMPLEX PRODUCT ENZYME SUBSTRATE ENZYME- SUBSTRATE COMPLEX PRODUCT Use the word bank to complete the following table: SUBSTRATE ENZYME PRODUCT TYPE OF REACTION AMYLASE LIPASE PEPSIN PHOSPHORYLASE 13

14 WORDBANK WORDS CAN BE USED MORE THAN ONCE slowly catalase water speed Active site Fatty acids substrate starch Glucose-1- phosphate enzymes fat product Built up protein catalysts maltose synthesis degradation peptides Broken down oxygen specific Enzymes in biotechnology this is the use of micro-organisms to make products that are useful to man. detergents contain ENZYMES to digest the large molecules in into smaller molecules which are washed away. The enzymes used are made by. Huge numbers of bacteria are grown in large. In some people the can cause an reaction. To prevent this, the enzymes are now enclosed in a harmless coating of. Biological washing powders claim to save. This is important for the. 14

15 Cheese making Cheese is solid but is made from liquid milk. Milk must be. This is when milk turns acidic and the acid clots the proteins into solid, leaving a clear liquid. is used to make the milk curdle. Rennet is a complex of which is made in the of mammals. It helps to separate the milk into curds and whey. There are several sources of rennet: RENNET RENNET GENETICALLY ENGINEERED which can produce rennet. WORDBANK WORDS CAN BE USED MORE THAN ONCE bacteria enzymes biotechnology wax energy biological curdled allergic fermenters environment stains rennet curds stomach fungal yeast calf whey 15

16 Temperature and enzymes Enzymes are affected by a change in. If the temperature is particularly low, the enzyme activity will be very. As the temperature the enzyme activity increases, but only up to a certain point. The temperature at which the enzyme works at its quickest is called the temperature. Most enzymes have an optimum temperature around 37 o C. When proteins are heated their structure changes (think of an egg!) Since enzymes are proteins this is also true for them. Their structure changes permanently and the enzyme can no longer function, It is Tem perature v Enzyme Activity Increasing rate of Reaction Increasin g enzyme ac tivity Optimum temperature Enz yme being dena tu red Temperature ( o C) 38 Enzymes and ph Like temperature, enzymes have an ph, i.e. a ph when they are most efficient. The optimum ph varies from enzyme to enzyme. 16

17 Our system has a range of ph s as the food passes through it, and this creates ideal conditions for enzymes. Effect of ph on Enzymes 100 Enzyme Activity (%) Pepsi n Catalase Lipase ph WORDBANK WORDS CAN BE USED MORE THAN ONCE human denatured optimum specific slow digestive increases temperature 17

18 Respiration Respiration is the process by which cells release e from food. Respiration takes place inside all living cells. Living things need energy:-to build up molecules using smaller ones. in animals, to enable to contract. in mammals and birds, to maintain a steady body in colder surroundings The main source of energy in cells is. There are two types of respiration:- 1. Aerobic Uses to release energy from glucose. Glucose + oxygen + water + energy 2. Anaerobic Takes place in the absence of. WORDBANK (words may be used more than once) Larger Carbon Dioxide Aerobic Oxygen Temperature Glucose Muscles 18

19 ATP The chemical energy in glucose is released in a series of controlled steps Some energy is lost as energy The chemical energy is not used directly by the cell but is stored through the formation of a molecule called. When the energy is released from glucose, some of it is used to join the inorganic phosphate to the ADP to make. The energy used to join the phosphate to the ADP is stored in a high bond. The high energy bond is broken and the stored energy is. When energy once again becomes available to the cell (eg.from the breakdown of glucose) the ADP and Pi are put back together to make. Energy used up Low energy compound + High energy compound Energy Released The Role of ATP ATP is the energy source for: Muscle Cell Building up (synthesis) of proteins Transmission of impulses WORDBANK (words may be used more than once) Energy Carbon Dioxide ATP Heat Pi Nerve Division Contraction Released Oxygen Enzyme ADP 19

20 Aerobic respiration Stage 1- Glycolysis A glucose molecule is broken down by a series of controlled reactions into two molecules of acid. This process is called glycolysis and does not require o. It also releases enough energy to regenerate molecules of ATP from ADP + Pi Gkycolysis takes place in the. Glucose Series of enzyme controlled reactions 2 ADP + 2 Pi 2 ATP (Pyruvate) Stage 2 In total, 38 molecules of ATP are produced from the breakdown of molecule of glucose Glycolysis only produces 2 ATP so the remaining ATP must be produced in the second stage Stage 2 is where acid is broken down. This only happens when oxygen is present Stage 2 of Aerobic Respiration Pyruvic Acid + Oxygen Series of enzymecontrolled reactions 36ADP + 36Pi 36 + Water 20

21 WORDBANK (words may be used more than once) Enzyme Oxygen 1 Mitochondrion Respiration 2 Breakdown Glycolysis Glucose Pyruvic Pi acid Carbon dioxide 36 21

22 Anaerobic Respiration Anaerobic respiration occurs in the absence of It has two main disadvantages:- It releases less It makes poisonous products. Anaerobic respiration in plants GLUCOSE + + takes place as normal, releasing ATP. Pyruvic acid is then broken down into and carbon dioxide. This is an process. Anaerobic respiration in Yeast i) Making alcohol (eg. - and beer) Yeast is added to a sugar solution Yeast acts on the s When there is no o (anaerobic conditions), yeast converts sugars to a and and gains some energy. The levels of alcohol eventually build up and kill the y b) Breadmaking 22

23 Dough (sugar + flour + salt + water + yeast) Proving Baking Bubbles of carbon dioxide get trapped in the dough and cause it to. The yeast also releases small amounts of but this evaporates when the bread is baked. 2. Anaerobic respiration in animals occurs as normal, releasing ATP molecules. Pyruvic acid is broken down to which causes. This is a process. The lactic acid is converted back to pyruvic acid when is available. Glucose Anaerobic respiration Converted back when oxygen available 23

24 WORDBANK (words may be used more than once) Enzyme Oxygen 1 Mitochondrion Respiration Energy Breakdown Glycolysis Waste Pyruvic Pi Reversible Debt Glucose Sugar Alcohol Cytoplasm Yeast Aerobically Lactic Acid Anaerobically 2 Wine Fatigue Irreversible Carbon dioxide ethanol 24