Biology Topic 2 - Organisation Flashcards
What is a tissue?
Group of cells with a similar structure and function
Whats an organ?
Group of tissues working together for a specific function
Whats an organ system?
Organs which work together to form organisms
Example of a tissue
Muscle cells work together to make muscle tissue
Example of an organ?
The stomach contains stomach tissue and glandular tissue which release enzymes
Example of organ systems
Digestive systems
What nutrients do foods contain?
Carbohydrates, protein and lipids
What must occur so nutrients to be absorbed into the blood stream
Due to them being large molecules, they must be digested
What happens during digestion, for large food molecules to be broken down
During digestion, large food molecules are broken down by enzymes so they can be absorbed into the bloodstream
Whats the mouth?
Food is chewed in the mouth, which enzymes in the saliva begin to digest the starch into smaller sugar molecules
Where does the food go after the mouth?
Goes down the oesophagus
Where does the food go after the oesophagus
Goes into the stomach.
What occurs in the stomach?
Enzymes begin the digestion of proteins.
Also, contains hydrochloric acid which helps the enzymes digest proteins. This occurs for several hours, and the stomach churning action of the stomach muscles turns the food into a fluid increasing the surface area for enzymes to digest
Where does the fluid go after the stomach?
Goes into the small intestine
Where are the chemicals realeased from in the small intestine?
Pancreas and liver
What does the pancreas do?
Produce digestive enzymes
What does the liver do?
Releases bile which helps to speed up the digestion of lipids. Bile also neutralises the acid released from the stomach
What do the walls of the small intestine do?
Release enzymes to continue the digestion of protein and lipids
What occurs in the small intestine?
The small food molecules produced by digestion are absorbed into the blood stream either by diffusion or active transport
Where does the fluid go after the small intestine?
Makes its way to the large intestine where all water is absorbed into the blood stream
Whats after the large intestine
Finally all feaces are released from the body
What are the products of digestion used by the body for?
Build new carbohydrates, lipids and proteins
Some of the glucose is used for respiration
What do enzymes do?
Catalyse chemical reactions
What are enzymes?
Large protein molecules which have a groove on their surface called the active site
What does the active site bind to?
A substrate
Whats the lock and key theory?
The shape of an activate site is structured to fit a specific substrate
What enzymes are protein broken down by?
Proteases
Where are proteases found?
The stomach
Pancreas
Small intestine
What are the structure of protein?
Long chains of amino acids
What does protease do to proteins?
Converts the protein back to the individual amino acids, which are then absorbed into the bloodstream
This is then absorbed by body cells and joined in different orders to make human proteins
Structure of starch molecules
Chain of glucose molecules
What enzyme are starch broken down by?
Carbohydrases, in specific amalyse
What is produced when carbohydrates like starch are digested?
Simple sugars/Glucose
Where is amalyse found?
Saliva
Pancreas
Structure of a lipid molecule?
Molecule of glycerol attached to three fatty acid molecules
What enzyme are lipids digested by?
Lipase
Whats produced when lipids are digested?
Glycerol and fatty acids
Where is lipase found?
Pancreas
Small intestine
Where is bile made?
Liver and stored in gall bladder
What does bile do?
Help speed up the digestion of lipids but is not an enzyme
What does bile do to lipids?
Bile emulsifies the lipid into small droplet molecules
Advantages of bile emulsifying lipids?
Massively increases surface area of the lipid droplets which increases the rate of reaction by lipase enzyme
How does bile neutralise stomach acids?
Bile is an alkaline and neutralises hydrochloric acid in the stomach, creating better conditions for enzymes in the small intestine to digest food efficiently
What happens if we increase the temperature of an enzyme
The rate of reaction of the enzyme increases
Why does increasing the temperature, cause a faster rate of reaction
The enzyme and substrate are moving with more kinetic energy and are moving faster so there are more collisions per second between the substrate and active site
Whats the optimum temperature?
Certain temperature which the enzyme is working at the fastest possible rate and the maximum frequency of successful collisions between the subtrate and the active site
Whats the optimum temperature for most human enzymes
37°C
What happens if an enzymes temperature is past its optimum
The activity of the enzyme rapidly decreases to zero and becomes denatured
What occurs if an enzymes temperature is past its optimum?
The activity of the enzyme rapidly decreases to zero and the active site becomes denatured
Why does an enzyme become denatured as its temperature is past optimum?
The enzyme molecule vibrates and the shape of the active site changes and the substrate cant fit perfectly into the active site
What happens if the PH of an enzyme is less or more than optimum?
If the pH is too acidic or too alkaline then the activity drops to zero due to the active site becoming denatured
Example of an enzymes which works best at alkaline and acidic pH levels?
Acidic: Protease enzyme in the stomach
Alkaline: Enzyme release from the pancreas into the small intestine
How has the small intestine been adapted?
.Has a length of around 5m which provides a very large surface area for absorption of the products of digestion
.Contains millions of villi which increase the absorption of molecules
How have villis been adapted?
On the surface has a microvilli which increase the surface area further
Has very good blood supply so the bloodstream rapdily removes products of digestion and increase concentration gradiant
Thin membrane for short diffusion path
What occurs if a molecule cant be absorbed by diffusion?
Are absorbed by active transport
Circulatory system of a fish
Single circulatory system
Doxygenated blood is pumped from the heart to the gills which become oxygenated
Gills sends oxygenated blood back to the organs where the oxygen diffuses out od the blood and into the body cell
The blood now returns to the heart
What is the disadvantage of single circulatory systems?
The blood loses a lot of pressures as it passes through the gills. This means it delivers the oxygenated blood slowly and cant deliver a lot of oxygen
Benefits of the double circulatory system?
The blood passes to the heart twice and the oxygen can be transferred rapidly
Process of the double circulatory system?
Deoxygenated blood Is pumped into the right atrium then right ventricle to be pumped to the lung for gas exchange
Oxygenated blood flows into the left atrium then the left ventricle which pumps oxygenated blood around the body
Structure of the heart
Muscular walls to provide a strong heartbeat
Muscular wall is thicker on the left ventricle because blood needs to be pumped around the whole body rather than just to the lung like the right ventricle
4 chambers which seperate oxygenated and deoxygenated blood
Valves to make sure blood doesn’t flow backwards
coronary artery cover heart to provide own oxygenated blood supply
Process of the heart pumping blood around the whole body
Blood flows into the right atrium through the vena cava, and left atrium through the pulmonary vein
Atria contract forcing blood into ventricles
Ventricles contract pushing blood in the right ventricle into the pulmonary artery to be sent to the lungs, and the left ventricle into the aorta to go around the body
As this happens the valves close to not allow any backflow
Natural resting heart rate?
70 BPM
What is the heart rate controlled by?
Group of cells found in the right atrium which act as a peacemaker.
How does the peacemaker control the heart rate?
Provide stimulation, through small electrical impulses which pass as a wave across the heart muscle causing it to contract
What happens without a peacemaker?
Heart would not pump fast enough to deliver enough oxygen around the body