Organisation Flashcards
What is tissue?
A tissue is a group of similar cells that work together to carry out a particular function. It can include more than one type of cell.
What are some examples of tissues in mammals?
- Muscular tissue (contracts)
- Glandular Tissue (makes and secretes chemicals)
- Epithelial Tissue (covers some part of body)
What is an organ?
A group of different tissues which work together to perform a certain function
What tissues are the organs in the stomach made of?
- Muscular Tissue moves stomach wall to churn food
- Glandular Tissue makes digestive juices to digest food
- Epithelial tissue covers outside and inside of stomach
What is an organ system?
A group of organs working together to perform a particular function
Name the human organ systems:
- digestive system
- Circulatory system
- Respiratory system
- Excretory system
- Nervous system
- Reproductive system
- Digestive system
- Endocrine system
- Lymphatic system
- Immune system
- Muscular/skeletal system
Why are enzymes useful?
They act as a biological catalyst
Define Catalyst:
A substance which increases the speed of a reaction without being changed or used up in the reaction. Lowers activation energy required for a reaction.
What are enzymes made of?
Enzymes are all large proteins and all proteins are made up of chains of amino acids. These chains are folded into unique shapes, which enzymes need to do their jobs
What do chemical reactions with enzymes usually involve?
Substrates being split apart(metabolic) or joined together(catabolic)
What is the name of the place where the substrate fits into the enzyme?
Active site
Why do enzymes usually only catalyse one specific reaction?
Because for an enzyme to work, the substrate has to fit into its active site. If the substrate doesn’t match the enzymes active site, then the reaction won’t be catalysed
What is the “induced fit” model of enzyme action?
Where the active site changes shape a little as the substrate binds to it to get a tighter fit.
How does an enzyme become denatured with temperature?
Increasing the temperatures, increases the rate of a reaction at first. However, if it gets too hot, some of the bonds holding the enzyme together break. This changes the shape of the enzymes active site, so the substrate won’t fit any more.
What condition, other than temperature effects the functionality of an enzyme?
Ph. If it is too high or low, the Ph interferes with the bonds holding the enzyme together. This changes the shape of the active site rendering the enzyme denatures
What are the three types of muscle cells?
Cardiac muscle cells, Skeletal muscle cells, Smooth Muscle Cells
What are the main organs in the digestive system in chronological order?
Mouth-Oesophagus-Stomach-Liver-Duodenum-Ileum-colon-rectum
What digestive process happens in the mouth?
chewing (mechanical) increases surface area of food to increase digestion by enzymes in the mouth (amylase)
What digestive process happens in the oesophagus?
peristalsis (contracts and relaxes to push food down)
What digestive process happens in the liver?
Bile is produced (stored in gall bladder) which goes down the bile duct and into duodenum
What digestive process happens in the duodenum?
pancreatic produced enzymes operate in the duodenum-amylase,protease,lipase
What digestive process happens in the ileum?
glucose,minerals and nutrients are absorbed
What digestive process happens in the in the colon?
water is absorbed as the bloodstream needs it
What digestive process happens in the rectum?
Faeces is stored there until it is ready to pass out of anus
What does amylase do?
Catalyses the breakdown of starch into simple sugars e.g. glucose
What does protease do?
Catalyses the breakdown of protein into amino acids
What does lipase do?
Catalyses the breakdown of lipids into fatty acids and glycerol
How does the substrate concentration affect the rate of a reaction?
Increased substrate concentration results in a faster rate of reaction up to certain point where this rate plateaus
Why does the rate of reaction/concentration of substrate graph plateau?
Because of limiting factors. This could be enzyme concentration or temperature for example.
How does the enzyme concentration affect the rate of a reaction?
Increased enzyme concentration results in a faster rate of reaction up to certain point where limiting factors come into play
How do you test for starch?
Add iodine solution. If starch is present, the iodine will turn from brown/orange to a blue-black colour
How do you test for reducing sugars?
Add Benedict’s solution (10 drops) to food sample in a test tube and place tube in a water bath(75 deg) for 5 minutes. If sugar is present it will produce a brick-red or yellow or green precipitate depending on how much sugar is in the food.
How do you test for protein?
Add biuret agent(2cm^3) to sample(2cm^3) and gently shake. If protein is present, the soltution will turn from blue to pink or purple .
How do you test for lipids?
Add three drops of Sudan III stain solution to the test tube with the sample(5cm^3) and gently shake. If lipids are present, the mixture will separate into two layers, the top layer will be bright red.
What is the danger with heating the boiling tube with Benedict’s solution testing for sugars?
If the tube is boiled for a long time, the starch present may break down into sugar and test positive
Describe and explain the lock and key theory?
The theory explains why enzymes are specific because both the substrate and enzyme have a unique shape like a lock and key. The key represents the substrate and the lock represents the enzyme’s active site. Only the substrate with the specific shape that fits exactly into the active site of the enzyme will form an enzyme-substrate complex.
After a reaction with an enzyme, what leaves the active site?
The product
What is denaturing of an enzyme?
Permanently changing the shape of an enzyme so it no longer compliments its substrate
What is the importance and function of the lungs?
The lungs are important as a gas exchange organ. It is where oxygen is able to diffuse into the blood, and carbon dioxide is excreted.
How are the lungs adapted for gas exchange?
- Have millions of alveoli (small air sacs) to increase the surface area
- Good blood supply (capillaries) reducing the diffusion distance of the gases
- The lungs are ventilated when we breathe to maintain a high concentration gradient of oxygen
What is the importance and function of the heart?
The heart is important because it transports oxygen, carbon dioxide and other important molecules through the body by pushing blood. It is a muscular pump.
What controls the heart beat?
A small group of cells called a pacemaker found in the right atrium. They initiate the contraction of the heart muscle with small electrical impulses.
Describe what happens during a heart beat sequence:
The atria contract, forcing blood into the ventricles. Then, the ventricles contract forcing blood into the arteries (pulmonary artery and aorta).
What is the function of the valves in the heart?
They prevent blood going the wrong way in the heart
What side of the heart has thicker muscle and why?
The side with the left atrium and ventricle so that more force can be applied to push the blood further
What separates the two sides of the heart, preventing oxygenated and non-oxygenated blood contamination?
The septum
What carries the oxygenated blood from the lungs into the heart?
The pulmonary vein
What carries the oxygenated blood from the heart to the body?
The aorta
What carries the de-oxygenated blood from the body into the heart?
The Vena Cava
What carries the de-oxygenated blood from the heart to the lungs?
The pulmonary artery