levels of organisation and cell structure Flashcards
(42 cards)
how does active transport use its energy
Active transport uses energy to move substances against a concentration gradient.
how are protein carriers and enzymes alike
they are able to recognize a specific shape and select them from a mixture
Why is active transport specific
active transport is specific so that the cell can “choose” which molecules to absorb from its surroundings
do red blood cells have a nucleus
no
does the nucleus control the cells activities
yes
what is an organelle
A component of a cell with a specific function
what are examples of organelles
Nucleus, Mitochondria, Chloroplast
what is a tissue
A group of similar cells which together perform a particular function
what is an organ
A structure made up of a collection of tissues, which performs a particular function.
what is an organ system
A collection of several organs working together to perform a particular task
what is diffusion
the movement of particles from a place of high concentration to a place of low concentration
what are factors effecting diffusion
Concentration gradient
Temperature
Distance particles must travel
what speeds up diffusion
Large concentration gradient
Higher Temperature
Short distance
what is biological diffusion
Dissolved substances have to pass through the partially permeable cell membrane to get into or out of a cell
what is digestion
Digestion breaks down large food molecules into smaller molecules that can be easily absorbed.
what do the villi do
in the small intestine they increase the overall surface area for maximum absorption and have a very good blood supply to absorb the nutrients
where does the oxygen from inhaled air go
the oxygen diffuses through the lungs and into the bloodstream before then being transported throughout the body
how does carbon dioxide exit the body
diffuses from body tissue into the lungs and is then exhaled by the lungs
what are the alveoli
tiny air sacs at the end of the bronchioles in which gas exchange occurs
what are the alveoli’s adaptations that make gas exchange more efficient
very thin(only one cell thick), they are covered by a network of fine capillaries(enabling gases to pass directly between the lungs and bloodstream), they are moist(encouraging gas molecules to easily dissolve) and they have a large combined surface area(allowing large amounts of gases to be exchanged)
what is the placenta
an organ that develops in the uterus during pregnancy
what does the umbilical chord connect
it connects the placenta to the foetus
what does the umbilical chord allow to happen
it enables nutrients and oxygen to pass to the foetus via diffusion and waste substances to diffuse back the other way
what is a synapse
a junction between two neurones across which electrical signals must pass
