B2 organisation Flashcards
what are cells?
cells are the basic building blocks that make up all living organsisms
what is a tissue?
a tissue is a group of similar cells that work together to carry out a particular function.
1)muscular tissue which contracts to move whatever its attached to
what is an organ?
an organ is a group of different tissues that work together to perform a certain function
1)muscular tissue which mmoves the stomach wall to churn up food
what is an organ system?
and organ systems is a group of organs that work together to perform a particular function
e.g. the digestive system made up of glands, stomach, intestines, liver.
what is a catalyst?
a catalyst is a substance which increases the speed of a reaction, without being changed or used up in the reaction
why do enzymes only usually catalyse one reaction?
they have a specific active site that only fits one substrate
what does it mean when an enzyme has been denatured?
its active site has changed
name three places amylase is produced in the body
salivary glands
pancreas
small intestine
what do carbohydrases break down?
carbohydrases convert carbohydrates into simple sugars
what do proteases break down?
proteases convert proteins into amino acids
what do lipases break down?
lipases convert lipids into glycerol and fatty acids
where is bile stored?
gall bladder
where is bile produced?
liver
name the solution that is used to test for sugars?
benedicts solution
name the solution that is used to test for starch?
iodine solution
name the solution that is used to test for proteins?
biuret test
name the solution that is used to test for lipids?
sudan 111 test
what colour will the solution turn if sugar is present?
blue - green, yellow, brick red
what colour will the solution turn if starch is present?
browny-orange - black, blue black
what coloyr will the solution turn if protein is present?
blue - purple
what will happen to the solution if lipids are present?
the solution will separate and the top layer will be bright red
name the three types of blood vessel
arteries
veins
capillaries
name the tubes that split off the trachea
bronchi
explain the role that alveoli play in gas exchange
the blood passing next to the alveoli has just returned to the lungs from the rest of the body, so it contains lots of carbon dioxide and very little oxygen. oxygen diffuses out of the alveolus into the blood. carbon dioxide diffuses out of the blood into the alveolus to be breathed out.
explain why the circulatory system in humans is describes as a ‘double circulatory system’
it is two circuits joined together
why does the heart have valves?
to make sure the blood flows in the right direction, they prevent it flowing backwards
name the four chambers of the heart
right atrium, right ventricle, left atrium, left ventricle
explain the flow of blood into and out of the heart
- blood flows into the two atria, from the vena cava and pulmonary vein
- the atria contract, pushing the blood into the ventricles
- the ventricles contract, forcing the blood into the pulmonary artery and the aorta, and out of the heart
- blood flows into the organs through the arteries, and returns through veins
- the atria fill again and the whole cycle starts over
how is the resting heart rate controlled in a healthy heart?
a group of cells in the right atrium that act as a pacemaker, these cells produce a small electric impulse which spreads to the surrounding muscle cells, causing them to contract.
how are arteries adapted to carry blood away from the heart?
walls are strong and elastic
the walls are thick compared to the whole in the middle
contain thick layers of muscle
why do red blood cells not have a nucleus?
more room to carry oxygen
what do arteries do?
carry blood away from the heart
what do capillaries do?
involved in the exchange of materials at the tissues
what do veins do?
carry the blood to the heart
how are capillaries adapted?
tiny
permeable walls so stuff can diffuse in and out
walls are usually only one cell thick, increases rate of diffusion
how are veins adapted?
bigger lumen to help blood flow,
and thinner walls compared to arteries
