Organisation. Flashcards
What are cells?
Are the basic building blocks that make up all living organisms.
Define differentiation.
Process by which cells become specialised for a particular jobs, differentiation occurs during the development of a multicellular organism.
What do specialised cells form?
Tissues, which form organs which form organ systems.
What do large multicellular organism have?
Different systems inside them for exchanging and transporting materials.
What is a tissue?
Group of similar cells that work together to carry out a particular function. It can include more than one type of cell.
In mammals what is the muscular tissue?
Muscular tissue = contracts to move whatever it is attatched too.cGlandular tissue = makes and secretes chemicals like enzymes and hormones.
In mammals what is the epithelial tissue?
Epithelial Tissue = covers some parts of the body eg:the inside of the gut.
In mammals what is the glandular tissue?
Glandular tissue = makes and secretes chemicals like enzymes and hormones.
Define the term organ.
A group of different tissues that work together to perform a certain function.
The stomach is a organ made from what tissues?
Muscular tissue = moves the stomach wall to churn up food. Glandular tissue = makes digestive juices to digest food. Epithelial tissue = covers the outside and inside of the stomach.
Define the term organ system.
A group of organs working together to perform a particular function.
What organs is the digestive system made from?
Glands = eg:pancreas and salivary glands that produce digestive juices. Stomach and small intestine = digests food. Liver = produces bile Small intestine = absorbs soluble food molecules Large instestine = absorbs water from undigested food leaving faeces.
What happens in the bodys of living things?
Thousands of different chemical reactions. They can be carefully controlled to get the right amount of substancs.
How to make a reaction happen quicker?
Raising the temperature. Speeds up the useful reaction but also the unwanted ones too.
What do living things produce that act as biological catalysts?
Enzymes, they reduce the need for high temperatures and we only have enzymes to speed up the useful chemical reactions in the body.
What is a catalyst?
Is a substance which increases the speed of a reaction without being changed or used up in the reaction.
Define the term enzyme.
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 involve?
Things either being split apart or joined together.
What does every enzyme have?
An active site with a unique shape that fits onto the substance involved in a reaction.
Why do enzymes on catalyse one specific reaction?
For an enzyme to work the substrate has to fit into its active site. If the substrate does not match the enzyme active site, then the reaction won’t be catalysed.
What does the lock and key diagram show?
Model of enzyme action. It is simpler than how they reall work. In reality the active site changes shape as the substrate binds to it to get a tighter fit. -the induced fut.
What does changing temperature of enzyme reaction do?
Changes the rate of an enzyme catalysed reaction.
What happens if the temperature is too hot in a chemical reaction what happens to the enzymes?
A higher temperature increases the rate at first. If it gets too hot some of the bonds holding the enzym together break. This changes the enzymes active site so substrate wont fit anymore. This means it denatures.
What does it mean by optimum temperature?
Temperature the work best at.
How does pH affect enzymes?
If its too high or low the pH interferes with the bonds holdin genzyme together. This changes the shape of the acitve site and denatures the enzyme.
What is the optimum temperature enzymes work best at?
Neutral so pH 7 but not always. Eg: pepsin is an enzyme used to break down proteins in the stomach. It works best at pH 2 which means it is well suited to acidic conditions.
How to investigate the effect of pH on enzyme activity?
1= Put a drop of iodine solution on a heatproof mat and a tripod and gauze over the bunsen burner or use an electric water bath instead to control the temperature. 2= put a beaker of water on top of the tripod and heat the water until it is 35 degrees use a thermomoter to measure this. 3= Try to keep the temperature constant through the whole experiment. 4= Use a syringe to add 1cm cubed of amylase solution and 1cm cubed of buffer solution with a pH of 5 to a boling tube. 5= Using test tube holders put the tube into a beaker of water and wait for 5 minutes. 6= Next use a different syringe to add 5cm cubed of a starch solution to the boiling tube. 7= Immediately mix the contents of the boiling tube and start the clock. 8= Use continuos sampling to record how long it takes for amylase to break down all the starch. 9= to do this use a dropping pipette to add fresh sample from the boiling tube every 30 seconds and put a drop into a well. 10= when iodine solution remains browny orange, starch is no longer present. 11= Repeat whole experiment with buffer solutons of different pH values to see how pH affects the time taken for the starch to be broken down. 12= Remember to control any variables each time ie: concentration and volume of amylase solution to ensure it is a fair test and use a pH meter to accurately measure pH values.
What is rate a measure of?
How something changes over time.
How to calculate the rate of reaction?
1000/time units= s^-1