1. Cell Structure Flashcards
What is a eukaryotic cell?
- It has a nucleus.
- They usually have mitochondria.
- In plants cells only they have chloroplasts.
What is a prokaryotic cell?
- bacterial cell
- no nucleus
- genetic material is a single loop of DNA
Differences between prokaryotic and eukaryotic cells
(4)
- much smaller in size
- the genetic material is not enclosed in a nucleus
- the genetic material is a single DNA loop and there may be plasmids
- they do not contain mitochondria or chloroplasts.
What is a nucleus?
Controls all activities of the cell.
What is cytoplasm?
A liquid gel in which most of the chemical reactions take place.
What is cell membrane?
Controls what passes in and out of the cell.
What are mitochondria?
where aerobic respiration takes place
What are ribosomes?
Where protein synthesis occurs and synthesis for all other proteins in the cell.
What is a cell wall?
Made of cellulose it strengthens the cells and gives it support.
What are chloroplasts?
They absorb energy from the sun to make food by photosynthesis.
What is a permanent vacuole?
A space in the cytoplasm filled with cell sap that keeps the cells rigid to support the plant.
What is cell differentiation ?
the process by which a cell changes to become specialised for its job
What are specialised cells?
Cells specialised to carry out a particular function.
What are adaptations of root hair cells?
- long hair that sticks out into the soil which gives the plant a large surface area to increase the rate of absorption.
- They also contain lots of mitochondria, which release energy from glucose during respiration in order to provide the energy needed for active transport
What is the function of a root hair cell?
Enables plants to take in water and mineral salts.
What are the adaptations of a sperm cell?
- It has a middle section full of mitochondria to release energy.
- long tail and streamlined head to help it swim to the egg
- The acrosome in the head contains digestive enzymes so that the sperm can penetrate an egg.
What is the function of a sperm cell?
To fertilise egg cells.
What are the adaptations of red blood cells?
- cytoplasm contains haemoglobin to transport oxygen
- no nucleus - can contain more haemoglobin
- biconcave shape to maximise surface area
What is the function of a red blood cell?
To carry oxygen.
What does a red blood cell NOT have?
A nucleus.
What is the function of a nerve cell?
To send nerve impulses around the body.
what are the adaptations of nerve cells?
They are thin and long. This means they can carry messages up and down the body over large distances.
Nerve cells have branched connections at each end. These join to other nerve cells, allowing them to pass messages around the body.
They have a fatty (myelin) sheath that surrounds them. The fatty sheath increases the speed at which the message can travel.
What is the equation for magnification?
Magnification = size of image (I) / actual size (A)
What are fat cells?
Storage cells. They help animals to survive when food is in short supply.
What are the adaptations of fat cells?
- They have little amounts of cytoplasm - to leave room for large amounts of fat.
- They have very few mitochondria as they use little energy.
- They can expand when it fills up with fat.
What are specialised cells grouped together to form?
A tissue
What joins parts of the body together?
Connective tissue
What does nervous tissue do?
Carries information around the body.
What do photosynthetic cells do?
Make food by photosynthesis
What do storage tissues do?
Store extra food made as starch
How many micrometers are in a millimetre?
1000
Is a bacterium a prokaryotic or eukaryotic cell?
Prokaryotic
Which cells are smaller? Plant cells or bacterial cells?
Bacterial cells
What substance is the cell wall made of?
Cellulose
In bacterium cells, the role of mitochondria and chloroplast are taken over by…..
cytoplasm
what are plasmids
small rings of DNA
what to plasmids allow bacterial cells to do?
they allow bacterial cells to move genes from one cell to another
what is the diameter of a typical plant cell
0.1mm
what is the diameter of a typical animal cell?
0.02mm
what is the diameter of prokaryotic cell
0.002mm
