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Living and Growing (OCR Gateway) W Richards The Weald School
16/04/2017 Living and Growing (OCR Gateway) W Richards The Weald School
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16/04/2017 B3a Molecules of Life
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A Typical Animal Cell 4) Ribosomes – protein synthesis happens here 1)
16/04/2017 4) Ribosomes – protein synthesis happens here 1) Cytoplasm - this is where the reactions happen and these are controlled by enzymes 2) Nucleus – controls the cell’s activities 5) Mitochondria - energy is released here and there are LOTS of these in the liver and muscles 3) Cell Membrane – controls what comes in and out
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Genes, Chromosomes and DNA
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DNA Some facts: - Made up of paired bases
16/04/2017 Some facts: - Made up of paired bases - Contain instructions on what a cell does, how the organism should work etc - The instructions are in the form of a code - The code is made up from the four bases that hold the two strands together - The bases represent the order in which amino acids are assembled to make proteins - The sequence of bases determines the order in which a cell makes amino acids, which turn into proteins - There are about 20 amino acids in all, and different combinations produce different proteins
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Making proteins 1) DNA “unravels” and a copy of one strand is made
16/04/2017 1) DNA “unravels” and a copy of one strand is made 2) The strand copy is made to produce RNA 3) The copy (with its code) then moves towards the ribosome 4) The ribosome “decodes” the code which tells the ribosome how to make the protein 5) Amino acids are then joined together to form a polypeptide (protein)
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DNA Task: Find out how the structure of DNA was discovered, including:
16/04/2017 Task: Find out how the structure of DNA was discovered, including: An image of Crick and Watson with their original model A brief desciption of what Crick and Watson did to discover DNA How Franklin and Wilkins built on their work
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Watson and Crick 16/04/2017 We discovered the structure of DNA in We used data from other scientists (such as X-ray data showing that there were two chains wound in a helix) to come up with the double-helix structure. However, our discovery was not accepted by the scientific community until other scientists repeated and tested the work.
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B3b Proteins and Mutations
16/04/2017 B3b Proteins and Mutations
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Proteins Proteins are basically long chains of amino acids:
16/04/2017 Proteins are basically long chains of amino acids: Every different protein has its own number and sequence of amino acids which results in differently shaped molecules with different functions. Some example proteins: Name of protein Function Collagen Give structure Insulin Hormones Haemoglobin Carrier molecules
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Enzyme use in nature 16/04/2017 Enzymes are proteins that speed up chemical uses. Here are two important natural uses for them: Photosynthesis is catalysed by enzymes in the cells. Cells use glucose to generate energy – this process is called “respiration”. Respiration happens in mitochodria and is catalysed by enzymes.
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Introduction to Enzymes
16/04/2017 Enzymes are biological catalysts. They help the reactions that occur in our bodies by controlling the rate of reaction. An enzyme is basically a protein molecule made up of long chains of amino acids. These molecules are then “folded” to create a certain shape with high “specificity”: Enzyme The enzyme’s shape helps another molecule “fit” into it: Substrate This shape can be destroyed by high temperatures or the wrong pH:
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The “Active Site” 16/04/2017 Active site Enzyme Substrate
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Enzymes are denatured beyond 40OC
16/04/2017 Enzymes work best in certain conditions: Enzymes are denatured beyond 40OC Could be protease (found in the stomach) Could be amylase (found in the intestine) Enzyme activity Temp pH 400C The “Q10” value is a way of measuring the change to the rate of reaction: Q10 = Rate at higher temperature Rate at lower temperature
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Mutations 16/04/2017 Cells contain a nucleus and the nucleus contains genes that carry instructions for what that cell should do: Genes Some facts: Some genes are “switched off” and don’t do anything in that cell Genes basically tell the cell which proteins they should be producing Sometimes cells can “mutate” which may have a harmful effect on the cell and can be caused by natural or artificial means.
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Mutations 16/04/2017 Mutations are changes in the base sequence of the DNA molecule. They can be passed on to daughter cells through cell division. They will result in the wrong proteins being produced. Mutations can be caused by: - Ionising radiation (UV, X-rays etc) - Radioactive substances - Certain chemicals Effects: - Mostly harmful - Causes death or abnormality in reproductive cells - Causes cancer in body cells - Some CAN be neutral or even beneficial (e.g. the peppered moth)
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16/04/2017 B3c Respiration
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Respiration Introduction
16/04/2017 I enjoy taking samples using quadrats. In order to do this, I need energy. Where does this energy come from? Our energy comes from a process called respiration, which basically involves turning food and oxygen into energy and this reaction is controlled by enzymes.
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(Aerobic) Respiration
16/04/2017 All living organisms have to move, _____, reproduce etc. Each of these life processes needs ENERGY. ___________ is the process our bodies use to produce this energy: The glucose we need comes from ______ and the oxygen from _________. Water and carbon dioxide are breathed out. The MAIN product of this equation is _________. Respiration happens in _________ in cells. Glucose + oxygen water + carbon dioxide + ENERGY C6H12O6 + 6O H2O + 6CO2 + ENERGY Words – breathing, energy, grow, respiration, food, mitochondria
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The Effect of Exercise Heart rate/min Breathing rate/min Rest Exercise
16/04/2017 Heart rate/min Breathing rate/min 100 225 Rest Exercise Recovery 75 175 50 125 25 75 5 mins 10 mins 15 mins 20 mins During exercise the following things happen: heart rate increases, breathing increases and arteries supplying muscles dilate. These three things all help muscles to get the oxygen and glucose they need.
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Muscles and exercise 16/04/2017 When we exercise our muscles are supplied with more oxygen and glucose, increasing the rate of respiration. Respiration results in the production of ATP which is used as an energy source in cells. This process requires oxygen so the rate of respiration can be measured by measuring the rate of consumption of oxygen. RQ = Carbon dioxide produced Oxygen used The rate of respiration is controlled by enzymes. What are enzymes affected by?
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Anaerobic respiration
16/04/2017 Unlike aerobic respiration, anaerobic respiration is when energy is provided WITHOUT needing _________: Glucose lactic acid + a bit of energy This happens when the body can’t provide oxygen quick enough for __________ respiration to take place. Anaerobic respiration produces energy much _______ than aerobic respiration but only produces 1/20th as much. Lactic acid is also produced, and this can build up in muscles causing ______ and “excess post-exercise oxygen consumption” (“EPOC”), which explains why breathing and heart rates remain high after exercise. Words – debt, oxygen, fatigue, aerobic, quicker
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16/04/2017 B3d Cell Division
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Single celled or multi-celled?
16/04/2017 Advantages of being single-celled: Advantages of being multi-celled: Disadvantages of being single-celled: Disadvantages of being multi-celled:
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Cell Growth There are three ways in which a cell might “grow”:
16/04/2017 There are three ways in which a cell might “grow”: 1) Cell division: 2) Cell expansion: 3) Cell specialisation:
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Mitosis 16/04/2017 Each daughter cell has the same number of chromosomes and genetic information as the parent. Mammal cells are “diploid” – they have two copies of each chromosome
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Making DNA copies 2) New bases pair up with the exposed bases
16/04/2017 2) New bases pair up with the exposed bases 3) An enzyme bonds these bases together 4) Two identical pieces of DNA are formed 1) The double helix unzips
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Each daughter cell has half the number of chromosomes of the parent.
Meiosis 16/04/2017 Each daughter cell has half the number of chromosomes of the parent.
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Mitosis vs. Meiosis Mitosis: Meiosis:
16/04/2017 Mitosis: Used for growth and repair of cells Used in asexual reproduction Cells with identical number of chromosomes and genetic information are produced Meiosis: Used to produce gametes for sexual reproduction Each daughter cell has half the number of chromosomes of the parent
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Sexual Reproduction 16/04/2017 The human egg and sperm cell (“ HAPLOID GAMETES”) contain 23 chromosomes each and are created by meiosis. When fertilisation happens the gametes fuse together to make a single cell called a DIPLOID ZYGOTE. The zygote has 46 chromosomes (23 pairs) and continues to grow through mitosis.
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Words – food, swimming, sperm, specialised, digest
Eggs and sperm 16/04/2017 The female egg cell and the male sperm cell are examples of ____________ cells: The ______ cell is specialised in two ways: An acrosome that releases enzymes to ______ its way through the egg Nucleus The egg cell is basically an enlarged cell with massive _____ reserves Strong tail for ________ Words – food, swimming, sperm, specialised, digest
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B3e The Circulatory System
16/04/2017 B3e The Circulatory System
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The Circulatory system
16/04/2017 The circulatory system is responsible for pumping ______ around the body. We need blood to be taken around the body because blood contains ________ and _______. These are needed so that all the ____ in our bodies can produce _____ through _________. The main organs in the circulatory system are the _____, the lungs and the kidneys. Words – energy, heart, blood, glucose, respiration, oxygen, cells
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The four parts of blood 16/04/2017 1. RED BLOOD CELLS – contain haemoglobin and carry ______ around the body. They have no _______ and a large surface area. 2. PLATELETS – small bits of cells that lie around waiting for a cut to happen so that they can ____ (for a scab). 3. WHITE BLOOD CELLS – kill invading _______ by producing _________ or engulfing (“eating”) the microbe. These three are all carried around by the PLASMA (a straw-coloured liquid). Plasma transports CO2 and ______ as well as taking away waste products to the ______. Words – antibodies, clot, kidneys, oxygen, nucleus, glucose, microbes.
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The role of haemoglobin
16/04/2017 1) Red blood cells are packed with haemoglobin. When they are pumped to the heart the haemoglobin picks up oxygen (“oxyhaemoglobin”) 2) After the oxygen and glucose have been removed for respiration the blood is sent back to the heart and then to the lungs to start again
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The Double Circulatory System
16/04/2017 1) Blood gets pumped from the heart to the lungs and picks up oxygen 2) The blood is then taken back to the heart… Having a double circulatory system enables mammals to pump blood at higher pressure and with a greater flow rate. 3) The heart pumps the blood to the intestine (where oxygen and glucose are removed)… 5) After the oxygen and glucose have been removed for respiration the blood is sent back to the heart and starts again 4) … and to the rest of the body (where oxygen is removed)
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Arteries, veins and capillaries
16/04/2017 Arteries carry high pressure blood away from the heart. They have smaller lumen and no valves. Capillaries have thin walls (one cell thick) to allow glucose and oxygen to pass through. Also used to connect arteries to veins. “Lumen” Veins carry low pressure blood back to the heart. They have thinner, less elastic walls and have valves to prevent backflow of blood.
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The Heart 16/04/2017 1. Deoxygenated blood (i.e. blood without oxygen) enters through the vena cava into the right atrium 4. Oxygenated blood from the lungs enters through the pulmonary vein into the left atrium 2. It’s then pumped through the tricuspid valve into the right ventricle 5. It’s then pumped through the bicuspid valve into the left ventricle 3. It’s then pumped through the semi-lunar valve up to the lungs through the pulmonary artery 6. It’s then pumped out of the aorta to the rest of the body
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B3f Growth and Development
16/04/2017 B3f Growth and Development
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Revision of a Typical Animal Cell
16/04/2017 4) Ribosomes – protein synthesis happens here 1) Cytoplasm - this is where the reactions happen and these are controlled by enzymes 2) Nucleus – controls the cell’s activities 5) Mitochondria - energy is released here 3) Cell Membrane – controls what comes in and out
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A typical plant cell: 16/04/2017 Cell wall – made of cellulose which strengthens the cell Cell membrane – controls what comes in and out Chloroplasts (containing chlorophyll) – this is needed for photosynthesis Nucleus – controls what the cell does and stores information Large vacuole – contains sap and helps support the cell Cytoplasm – Chemical reactions happen here
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Plant cells vs. Animal cells
16/04/2017 Only plant cells have these: Both types of cell have these: 4) 1) 5) 6) 2) 3) Cell wall Cytoplasm Nucleus Chloroplasts Cell Membrane Large Vacuole
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Bacteria Consider a bacteria cell in more detail:
16/04/2017 Consider a bacteria cell in more detail: Bacteria contain cytoplasm and a membrane surrounded by a cell wall. The genes are NOT in a distinct nucleus and bacterial cells do not have mitochondria or chloroplasts.
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Measuring Plant Growth
16/04/2017 I’m bored of using quadrats now. I think I’ll measure the growth of this plant instead. How can I do it? There are a number of ways to measure plant growth, including measuring: Length/height Wet mass Dry mass What are the advantages and disadvantages of each?
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Measuring Human Growth
16/04/2017 Growth rate (cm/year) Age
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Adult Stem Cells 16/04/2017 It is also possible to have adult stem cells – these are unspecialised cells that can become specialised later (but they can’t form ALL types of cell) Adult stem cells can be found in places like bone marrow. White blood cell Egg cell (ovum) Ciliated epithelial cell Nerve cell (neurone)
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Should these embryos be treated as humans?
Stem cell research 16/04/2017 Stem cells are cells that have not yet specialised: These stem cells have the potential to develop into any kind of cell. The rest of the embryo is destroyed. Most of these embryos come from unused IVF treatments unless the stem cells are taken from bone marrow in adults. Embryo Egg and sperm Cloned embryos The ethical issue: Should these embryos be treated as humans?
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Human Growth vs Plant Growth
16/04/2017 There are many differences between the way humans grow and the way plants grow: Plants grow continually and won’t stop until they die Plant cells retain their ability to differentiate whereas animal cells lose it at an early stage Plant cell division is restricted to areas called meristems Humans have two main stages of growth: straight after birth and during adolescence Human growth occurs throughout the human
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Plant Growth Introduction
16/04/2017 Plants grow due to their cells dividing through mitosis. The cells then specialise into root hair cells, palisade cells etc. Unlike animals, plants continue to grow for the rest of their lives.
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Plant Growth - Meristems
16/04/2017 Plant growth occurs in areas called meristems. These meristems are “mitotically active”: This meristem causes the plant to grow upwards. This meristem causes the plant to grow in width. Cells from the meristem behave like stem cells – they can develop into any kind of cell. Cloned plants can be produced from these cells.
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16/04/2017 B3g New Genes for Old
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Selective breeding Friesian Jersey Hereford
16/04/2017 Friesian I raise cows. Each type of cow is good at a certain job. The Friesian cow produces large quantities of milk, the Jersey cow produces very nice milk and the Hereford cow produces lot of beef. Jersey If, for example, I want lots of milk I would only breed Friesian cows with each other – this is SELECTIVE BREEDING. The only trouble is that I’m reducing the “gene pool” by doing this. Hereford
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Examples of Selective Breeding
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Uses of Genetic Engineering
16/04/2017 “Genetic engineering” is the idea of transferring a gene from one organism into another in order to give it extra features, such as: With genetic engineering I can produce milk that contains: Extra protein Lower levels of cholesterol Human antibodies Other current examples of genetic engineering include transferring genes from carrots that are involved in humans producing vitamin A and putting them into rice instead and engineering crops that are resistant to herbicides.
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An example - Insulin 16/04/2017 Step 1: Using RESTRICTION ENZYMES “cut out” the part of the human chromosome that is responsible for producing insulin. Step 2: Using another restriction enzyme cut open a ring of bacterial DNA (a “plasmid”). Other enzymes are then used to insert the piece of human DNA into the plasmid. Step 3: Place the plasmid into a bacterium which will start to divide rapidly. As it divides it will replicate the plasmid and make millions of them, each with the instruction to produce insulin. Commercial quantities of insulin can then be produced.
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Should genetic engineering
16/04/2017 Should genetic engineering be allowed?
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Gene therapy often involves gametes – why is this controversial?
16/04/2017 Gene therapy is when diseases are treated by modifying a person’s genome. For example, take cystic fibrosis: E E E E 1) Take a disease-causing virus 2) Remove the genetic material that causes excessive mucus to be produced 3) Insert the genetic material that stops cells producing excess mucus 4) The virus then works on the cells in the lung Gene therapy often involves gametes – why is this controversial?
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16/04/2017 B3h Cloning
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Dolly the sheep 16/04/2017 My name is Dolly and I was born in I made history as I was the first mammal clone. In other words, I was a genetically-identical copy of my parent. Of course, clones have been around for many years as identical twins are basically clones:
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Cloning Animals Here’s how Dolly the sheep was cloned: Host mother
16/04/2017 Here’s how Dolly the sheep was cloned: Host mother Clone
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Applications of Cloning
16/04/2017 Animal organ donors – animal organs could be potentially cloned and modified so that they can be used in humans. Human cloning – cloning can be used to provide stem cells but these could be used to clone a human. Animals with desirable characteristics could be cloned.
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Cloning 16/04/2017 Should cloning be allowed?
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Words – clones, damp, independent, roots, identical
Cloning Plants 16/04/2017 Plants can reproduce ASEXUALLY. The offspring are genetically ________ to the parent plant and are called _________. Two examples: 1) This spider plant has grown a rooting side branch (“stolon”) which will eventually become __________. 2) A gardener has taken cuttings of this plant (which probably has good characteristics) and is growing them in a ____ atmosphere until the ____ develop. Words – clones, damp, independent, roots, identical
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Cloning Plants by tissue culture
16/04/2017 1) Scrape of a few cells from the desired plant 2) Place the scrapings in hormones and nutrients 3) 2 weeks later you should have lots of genetically identical plants
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