Cells Flashcards
What are eukaryotic cells?
They are cells found in plants, animals, fungi and protists.
What is a eukaryote?
It is an organism made up of eukaryotic cells.
What are prokaryotic cells?
They are cells found in bacteria.
What is a prokaryote?
It is a unicellular organism made up of prokaryotic cells.
What is so different about a prokaryotic cell compared to a eukaryotic cell?
Prokaryotic cells do not have a nucleus - instead they have a single DNA loop in the cytoplasm where genetic material is stored.
What are the small rings of DNA called in prokaryotic cells?
They are called plasmids which move between cells so genetic info can be shared.
What is missing in prokaryotic cells?
They don’t have mitochondria or chloroplasts.
What does the mitochondria do?
It is where respiration takes place in the cell.
What does the chloroplast do?
It is where photosynthesis takes place in the cell.
What does a eukaryotic cell contain?
A cell membrane, a nucleus, cytoplasm, mitochondria and chloroplasts.
What does the cell membrane do?
it controls the movements in the cell from in and out - selectively permeable.
What does the cytoplasm do?
It is where the cell’s chemical reactions take place.
What does the nucleus do?
It is the control centre of the cell which contains the genetic material - in chromosomes.
What is a sub-cellular structure?
A sub-cellular structures are things found in a cell.
What is in an animal cell?
An animal cell contains a nucleus, cytoplasm, mitochondria, ribosomes and a cell membrane.
What does a ribosome do?
Ribosomes are responsible for making proteins.
What type of respiration do mitochondria do in the animal cell?
Mitochondria uses aerobic respiration - process which uses sugar and oxygen to release energy in the mitochondria.
What is a famous phrase for the mitochondria?
The mitochondria is the powerhouse of the cell.
Along with an animal cells sub-cellular structures what else does an plant cell contain that a animal cell does not?
It contains a permanent vacuole, chloroplasts and a cell wall.
What does the vacuole do?
It is a fluid filled sac that stores water.
What do chloroplasts contain that is needed for photosynthesis?
They contain chlorophyll.
What does the cell wall do?
It surrounds the cell and increases the strength of the cell - it is made of cellulose.
What is inside a bacterial cell?
Flagella, cytoplasm, plasmids and a cell membrane and wall.
What is flagella?
It is a whip-like structure in bacterial cells that are used for movement.
What is cell differentiation?
Cell differentiation is the process where a cell develops new sub-cellular structures to let it perform a specific function.
What happens to a cell when cell differentiation happens?
It becomes specialised.
When does cell differentiation happen?
It happens during an organism’s development.
How does differentiation work in embryos?
Organisms start off as one cell and the cells divide to form embryos that differentiate to produce cells that can perform the body’s functions.
How are plants able to create new tissues?
As they keep their ability to differentiate throughout their life.
How does differentiation work in adult animals?
Their cells mostly divide - 1 into 2 etc - to replace cells and repair tissues - this is rare - CD is rare in adult animals.
How are sperm cells specialised?
They are specialised to fertilise egg cells.
How do sperm cells fertilise egg cells?
They need to travel long distances and break through to the egg cell and fertilise it.
What does the tail do in a sperm cell?
Used for motion - allows sperm cells travel through the egg cell.
What does the acrosome do in a sperm cell?
Contains an enzyme needed to penetrate an egg cell.
What does the middle section do in the sperm cell?
It is filled with mitochondria to provide the sperm with energy to get to the egg cell.
What does the head of a sperm cell do?
It contains the sperm cell’s nucleus - carries 1/2 of on organism’s genetic material - this combines with the egg cell’s half of genetic material to fertilise the egg cell.
How are nerve cells specialised?
To transmit electrical messages around the body.
What does the axon do in a nerve cell?
It is part of a cell that electrical signals travel along - long axons increases the distance that electrical signals can travel.
What does the myelin sheath do in a nerve cell?
It is a sheath made of material called myelin which surrounds the nerve cell - this stops the electrical nerve signals leaking out - increases speed of transmission of signals.
What do dendrites do?
Branches of a nerve cell - several spread outwards from the cell body to transfer electrical message to other neurons.
What are gaps between neurones called?
They are called synapses.
What is another word for a nerve cell?
Neurones.
What is another word for electrical messages?
impulses.
What do protein fibres do in a muscle cell?
They can contract which allows the muscle to move.
What does the mitochondria do in a muscle cell?
It generates lots of energy for motion.
What do root hair cells do?
Their structure allows the plant to absorb more water and they also allow plants to take in minerals it needs to survive.
Why don’t root hair cells have no chloroplasts?
Because root hair cells are located underground - they don’t have chloroplasts as there is no light for photosynthesis.
Why do root hair cells have long projections?
They have long projections that increase surface area that the plant can use to absorb water and minerals.
How are xylem cells specialised?
They are specialised to transport water up the stem of a plant and into the leaves.
What are xylem vessels made up of?
They’re made up a series of connected dead xylem cells - the end of the dead cells are broken to allow water to move through.
What does lignin do in xylem cells?
It is a substance that strengthens the cell walls of xylem cells.
What is the phloem specialised for?
They are specialised to transport food products to parts of the plant where they are needed.
What are phloem vessels made up of?
They are made up of columns of living cells.
What are the end walls of phloem cells made up of?
Small holes that allows food products to move up and down phloem vessels throughout the plant.
What is magnification?
It tells us how many times larger an image seen through an microscope is compared to the real object.
What is resolution?
The ability to distinguish between (tell apart) two or more objects that are close together.
What is the equation of magnification?
image size/real size
How does a light microscope work?
It passes light through a specimen and creates a magnified image using lenses.
How does an electron microscope work?
It passes electrons through a specimen and creates a magnified image.
