organisation

• What is a tissue

  A tissue is a group of similar cells working together to perform a common function
• What are the levels in f organisation in organisms from least complex to most complex


  1)organelles

  2)cells

  3)tissues

  4)organs

  5)organ systems
• organ systems examples

  Respiratory

  nervous

  cardiovascular

  skeletal

  muscular
• What is an organ

  An organ is a group of different tissues working together to perform a common function
• Why is the cardiovascular system considered an organ system

  The cardiovascular system is considered an organ system because it consists of a group of organs that work together to perform the common function of transporting substances around our body

  The blood contains the substances that need to be transported, the blood vessels contain the blood, and the heart provides the force to pump the blood around the body
• What is an organ system

  An organ system is a group of different organs working together to perform a common function
• what is an organelle

  sub-cellular structures that make up a cell
• What is a cell

  Come in all shapes and sizes and contain different combinations and numbers of organelles
• What is an enzyme

  An enzyme is a special type of catalyst (so it speeds up a chemical reaction without being used up) that is made by a living organism. We sometimes call them biological catalysts
• What is the induced fit model of enzyme action

  This is the improved model that scientists proposed

  It states that in order for an enzyme to catalyse a reaction, the enzymes active site actually changes shape slightly as it binds to the substrate
• What is the lock and key model of enzyme action

  This was the first model scientists proposed

  They thought that in order for an enzyme to catalyse a reaction, the substrate had to fit perfectly into the active site
• What do we call the complex that is formed when an enzyme binds to a substrate

  Enzyme-substrate complex
• When discussing enzymes what does complementary mean

  A substrate must be complementary to the active site of the enzyme

  This means that it is the right match, or fits the active site
• The rate of chemical reactions increases with temperature

  Why don’t we increase the temperature of our cells to increase the rate of chemical reactions

  1)heating our cells more would require a lot of energy

  2)higher temperatures could damage our cells

  3)higher temperatures would also speed up non-useful reactions

  We have already sort of done this, our body temp is 37 degrees which is much higher than the environment, but any higher wont be worth it
• What is a catalyst 


  A catalyst is a substance that increases the speed of a chemical reaction without being used up or changed in the process
• Why do organisms need enzymes

  As most chemical reactions are naturally very slow
• What is the name of the special region of an enzyme that binds to the substrate

  Active site
• Explain how high or low Ph can cause an enzyme to denature 


  1)High or low Ph can break the bonds holding the enzyme together

  2)This causes the enzyme and its active site to change shape

  3)This means the enzymes active site will no longer be complementary to the substrate

  4)This means it can no longer form an enzyme-substrate complex
• What is the optimum temperature of enzymes in the human body

  Around 37-38 degrees
• What does the term optimum mean for enzyme temperature

  The optimum temperature is the temperature that gives the highest enzyme activity
• What are the two main factors that affect enzyme activity

  1)Temeperature

  2)Ph
• What is Ph 


  A measure of the hydrogen ion concentration, or a measure of acidity
• What units do we use to measure the energy that we consume in food

  In the case of food, we often use calories
• What is the relationship between the terms: lipids, oils and fats 


  Lipids refers to both fats and oils

  if the lipid is solid at room temperature we can call it a fat, but if the lipid is liquid at room temperature we can call it an oil
• What is the role of fibre 


  Fibre helps food to move through our intestines, and helps prevent diarrhoea or constipation
• State and explain 3 factors that affect how much energy a person requires each day 


  1)activity level-the more active you are, the more energy you need

  2)age-teenagers often need a lot of energy because they are growing, whereas elderly people usually need less

  3)pregnancy-pregnant women need more energy because the baby is growing inside them requires a lot of energy
• Which type of nutrient provides most of the energy we need each day

  We get the majority of the energy we need each day from carbohydrates

  However, lipids are also used for energy, and even proteins can be broken down for energy if necessary
• roughly how much of our body mass is water

  70%
• What is the role of vitamin D and how is it made 


  Vitamin D helps us absorb calcium

  We can synthesis (make) vitamin D using sunlight
• Explain why it is important that we get enough iron in our diet 


  Iron is an important component of haemoglobin. Haemoglobin is the protein in red blood cells that allows them to transport oxygen around the body

  A lack of iron (and hence a lack of haemoglobin), can lead to anaemia-a condition in which we can’t transport enough oxygen to our tissues
• What do we mean by a balanced diet 


  A balanced diet is a diet that includes appropriate proportions of all the different biological molecules, including carbohydrates, proteins, lipids, vitamins, minerals, dietary fibre and water
• What is the main function of proteins 


  To provide the material for building things, such as organelles and cells

  This means proteins are for important development, growth and repair
• What is the role of vitamin A


  It is important in maintaining good vision, healthy hair and healthy skin
• What is the main use of carbohydrates

  To provide energy for chemical reactions
• what happens if we don’t get enough vitamin C 


  Vitamin C deficiencies can lead to scurvy
• Which 3 biological molecules do we need to consume in large quantities (other than water)

  Carbohydrates

  proteins

  lipids
• What are the similarities and differences between vitamins and minerals 


  Similarities: vitamins and minerals are both essential for healthy growth and required in small quantities

  Differences: vitamins are organic compounds, so are produced by living organisms and made from carbon atoms. Mineral ions are very simple charged particles and are not made up by living organisms
• What are the 2 main uses of lipids

  1)To provide energy for chemical reactions

  2)To insulate us from warm/cold
• What is the role of calcium

  Calcium helps to build strong bones
• What are biological molecules 


  Biological molecules are molecules found in living organisms, and are produced by cells