Organisation

• What is a tissue?

  A group of cells that perform a specific function.
• In plants, what are leaves examples of?

  organs
• What is an organ?

  A group of different tissues that work together to perform a specific function in the body.
• Which of the following organs are part of the cardiovascular system?

  Heart

  blood vessels
• Explain, using an example, why the digestive system is considered an 'organ system'.


  The digestive system is an organ system as it consists of a group of organs that work together to perform a particular function of digesting and absorbing food.

  For example the pancreas releases digestive enzymes which helps break down the food molecules whilst the small intestine absorbs the nutrients.
• Are most chemical reactions naturally fast or slow?

  Slow
• Give two reasons why we can't just make our cells even warmer to increase the rate of reactions?  

  Heating our cells more would require a lot of energy

  High temperatures can damage our cells

  Higher temperatures would also speed up non useful reactions
• What is the substance that increases chemical reactions?

  Catalyst
• What is the name of special region of an enzyme that binds to the substrate?

  Active site
• In order for an enzyme to catalyse a reaction, the active site of the enzyme must be _____________ to the substrate. 


  Complimentary
• At first, scientists thought that in order for an enzyme to catalyse a reaction, the substrate had to fit perfectly into the active site.

  What was the name for this model of enzyme action?

  The lock and key model
• We now know 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 do we call this model of enzyme action?

  The induced fit model
• What is pH?

  Measure of acidity
• What affect does extremely high pH have on enzymes?

  Denatures them
• Can enzymes be reused?

  Yes
• Explain how increasing the temperature can cause an enzyme to denature.

  High temperatures start to break the bonds holding the enzyme together

  This causes the enzyme and active site to change shape

  This means that the enzyme active site will no longer be complimentary to the substrate.
• What does the term 'optimum' mean for enzyme temperature?

  The temperature at which the enzyme activity is the highest.
• Which 3 of the biological molecules below do we need in large quantities?

  Carbohydrates, proteins, lipids
• Why do we need carbohydrates?

  To provide energy for chemical reactions
• Fats and oils together make the food group known as:

  Lipids
• Why do we need lipids?

  To provide energy for chemical reactions

  to insulate us and regulate our body temperature
• Which food group is the most important for growth and producing new cells?

  Proteins
• Which vitamin or mineral ion is important for good vision and healthy hair and skin?

  Vitamin A
• Which mineral is important for strong bones?

  Calcium
• Which disease can be caused by lack of vitamin C?

  Scurvy
• Explain why it is important that we get enough iron in our diet.

  Iron is an important component of haemoglobin

  haeloglobin is the protein in red blood cells that allows them to transport oxygen around the body
• Why do we need fibre?

  To help food move through our intestines
• What are the 3 main ways by which we lose water from the body? 

  Breathing, sweating, urinating.
• Which vitamin or mineral ion helps us to absorb calcium, and can be made by the body, using sunlight?

  Vitamin D
• Which three elements are found in carbohydrates?

  Hydrogen

  carbon

  oxygen
• Carbohydrates are broken down in both the mouth and the small intestine.


  True
• Is starch a type of carbohydrate, protein or lipid?

  Carbohydrate
• Is glucose a monomer or a polymer?

  Monomer
• Is glycogen a monomer or a polymer?

  Polymer
• What are the monomers that join together to form proteins called?

  Amino acids
• Proteins are mainly made from carbon, hydrogen, oxygen, and which other element? 

  Nitrogen
• Lipids are only broken down in the:

  Small intestine
• What is a polymer of glucose produced by plants?

  Starch
• Which two of the following are examples of protease enzymes?

  Trypsin and pepsin
• is bile an enzyme?

  No