Biology topic 2 Flashcards
(91 cards)
What is a large multicellular organism?
Cells are the basic building blocks that make up all living organisms.
Specialised cells carry out a particular function.
The process of a cell becoming a specialised is called differentiation, which occurs during the development of a multicellular organism.
The specialised cells, form tissues, which form organs, which form organ systems.
Large multicellular organisms, such as squirrels have systems inside them for exchanging and transporting materials.
What is a tissue?
A group of similar cells that work together to carry out a particular function. It can include more than one type of cell.
Give some examples of tissues in mammals, (humans)
Muscular tissue, contracts to move whatever it’s attached to.
Glandular tissue which makes and secretes chemicals like enzymes and hormones.
Epithelial tissue which covers some parts of the body, e.g. the inside of the gut.
What is an organ?
A group of different tissues that work together to perform a certain function.
What is an organ system?
A group of organs working together to perform a particular function.
Give an example of the organs found in humans (and other mammals) digestive systems.
Glands, such as the pancreas and the salivery gland, which produce digestive juices.
The stomach and small intestine, which digest food.
The liver, which produces bile.
The small intestine, which absorbs soluble food molecules.
The large intestine which absorbs water from undigested food, leaving faeces.
what is an enzyme?
A catalyst produced by living things
What is a catalyst?
A substance, which increases the speed of a reaction without being changed or used up in the reaction.
Can you describe in depth what is an enzyme is?
Living things have thousands of different chemical reactions, which need to be carefully controlled to get the right amount of substances.
You can make a reaction happen more quickly by raising the temperature, which would speed up the useful reactions, but also the unwanted ones. There’s also a limit to how far you can raise the temperature inside a living creature before it cells start to get damaged.
Living things produce enzymes that acts as a biological catalysts. Enzymes reduce the need for high temperatures, and we only have enzymes to speed up the useful chemical reactions in our bodies.
Enzymes are all large proteins and all proteins are made up of chains of amino acids. These chains of folders into unique shapes, which enzymes need to do their jobs..
Describe an enzymes shape
Chemical reactions involve things being split apart, or joined together.
Each enzyme has an active site within a unique shape that fits onto the substance involved in the reaction.
Enzymes only usually catalyse one specific reaction.
This is because for the 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.
In reality, the active site changes shape as little as the substrate binds it to get a tighter fit. This is called the induced fit model of an enzyme reaction.
Why do enzymes need the right temperature and pH?
Changing the temperature changes the rate of an enzyme catalysed reaction.
The temp increases at first, but if it gets too cold, some of the bonds holding enzyme together will break, changing the shape of the enzymes active site, so the substrate won’t fit anymore (enzyme is denatured).
All enzymes have an optimum temperature that they work best at.
The pH also affects enzymes, it interferes with the bonds, which could lead to an enzyme, becoming denatured.
Enzymes all have an optimum pH, they work best at (neutral pH7). However, pepsin is used to break down proteins in the stomach (enzyme), it works best at PH 2), meaning it’s well suited to the acidic conditions there.
How do you calculate the rate of reaction?
1000 divided by time
How do digestive enzymes break down big molecules?
Starch, proteins and fats are big molecules. They’re too big to pass through the walls of the digestive system so digestive enzymes break these big molecules down into smaller ones like sugars, amino acids and fatty acids.
The smaller soluble molecules can pass easily through the walls of the digestive system, allowing them to be absorbed into the bloodstream.
What is amylase? Where is it made?
It’s an example of a carbohydrates because it breaks down starch. It’s made in three places; the salivery glands, the pancreas, the small intestine.
What is the equation for how maltose is made?
The enzyme amylase converts carbohydrates, such as starch into simple sugars called maltose.
Where are proteases made? (Enzyme)
Three places;
The stomach
The pancreas,
The small intenstine.
What is the equation for producing amino acids?
The enzyme protease, converts proteins into amino acids.
Where are lipases made? (Enzyme)
The pancreas and the small intestine
What is the equation for making glycerol and fatty acids?
The enzymes lipases, converts lipids (fats and oils), into glycerol and fatty acids.
What are the products of digestion used for in the body?
They can be used to make new carbohydrates, proteins and lipids. Some of the glucose that’s made is used in respiration.
What is bile and what does it do?
Bile is produced in the liver. It’s stored in the gallbladder before it’s released into the small intestine. The hydrochloric acid in the stomach makes the pH too acidic to work properly. Bile is alkaline - it neutralises the acid and makes conditions alkaline. The enzymes in the small intestine work best in these alkaline conditions.
It emulsifies fats, breaks the fat into tiny droplets, giving a much bigger surface area of fat for the enzyme lipase to work, which makes its digestion faster.
What are enzymes in the digestive system produced by?
Specialised cells in the glands, and in the gut lining
What are the four different enzymes in the body you need to know?
amylase, carbohydrase,
protease,
lipase
What are the salivery glands?
They produce amylase enzyme in the saliva
