science hw cards Flashcards
Name and describe 3 ways the human body defends against the entry of pathogens.
Skin – barrier, nose - nasal hairs , mucus and cilia, trachea & bronchi – mucus to catch, cilia to remove from lungs, stomach - HCl acid kills.
What is an antigen
A protein on the surface of a pathogen.
Why are dead or inactive pathogens used in a vaccine
To stimulate white blood cells to make antibodies without causing the disease.
why will the antibody produced for measles not be effective in other diseases
Antibody has a specific shape which fits with a specific antigen.
What is an antibiotic and what is it used for
kills bacteria inside the body without harming the cell
define Organism
A group of organ systems working together.
define Organ system
A group of organs working together to perform a specific function.
define Organ
A group of tissues working together to perform a specific function.
define Tissue
A group of similar cells with a similar structure and function.
define Cell
The smallest structural and functional unit of an organism.
What is digestion?
Large insoluble molecules are broken down into smaller soluble ones.
What is an enzyme?
A biological catalyst – they speed up the rate of reaction without being used up.
What biological molecule are enzymes made of?
Proteins.
What is the active site of an enzyme?
It is where the substrate binds
What is a substrate?
Substance (chemical) that the enzyme acts on.
What are the products of digestion used for in the body?
They are used to build new carbohydrates, lipids and proteins in the body. Glucose is used in respiration.
What does denatured mean?
That the active site of the enzyme has changed shape so the substrate cannot fit.
How does increasing the temperature affect enzyme activity?
Initially it increases the rate of reaction due to increased collisions between the enzyme and substrates, if the temperature is too high the enzyme will denature.
How does pH affect enzyme activity?
Enzymes have optimum pH conditions, if these are too alkaline or acidic the enzyme denatures
What is the role of bile in digestion?
It neutralises stomach. (hydrochloric) acid and emulsifies fats.
Where in the body is bile made?
Bile is made in the liver and stored in the gall bladder.
What is a double circulatory system?
Where blood from the heart is pumped to the lungs and the body at the same time.
What is a pacemaker?
A group of cells in the right atrium that controls the heart rate.
What is the role of the coronary arteries?
To supply oxygenated blood to the heart muscle.
