B1 - Cell Biology Flashcards
What are eukaryotic cells?
Cells which contain their genetic information inside a nucleus
Give examples of eukaryotic cells
Plant, animal and amoebae cell
What are prokaryotic cells?
Cells which don’t contain a nucleus and have their genetic information floating in the cytoplasm
Give an example of a prokaryotic cell
Bacterial cells
Is the bacteria smaller, equal in size or larger than animal and plant cells?
They are much smaller
What is the function of the nucleus?
Stores genetic information
What is the function of the cytoplasm?
This is where the chemical reactions take place
What is the function of mitochondria?
They release energy from glucose in aerobic respiration
What is the function of ribosomes?
They make proteins
What is the function of the cell wall?
To give the cell strength
What is the cell wall made up of?
Cellulose
What is the function of chloroplasts?
Carry out photosynthesis
What do chloroplast contain?
The pigment chlorophyll
What is the function of chlorophyll?
Capture the sunlight energy to do photosynthesis
What is the function of a permanent vacuole?
Contains cell sap and gives the cell structure and strength
Which sub cellular structures are found in plant cells but not in animal cells?
Cell wall, permanent vacuole and chloroplasts
What is the cell wall in bacterial cells made up of?
Peptidoglycan
What is a plasmid in a bacterial cell?
A small ring of DNA found in bacterial cells
What is the function of the flagellum in bacterial cells?
To allow movement
What are the two types of microscopes?
Electron and light
Why is the electron microscope better than the light one?
It has a higher magnification and resolution
What does a higher magnification mean?
It can see smaller objects in more detail
What does a higher resolution mean?
You can see things more clearly
How do you calculate the magnification?
Image size / actual size
What are the units of magnification?
X
How many chromosomes are there in a normal body cell?
46
How many pairs of chromosomes are there in a normal body cell?
23
What is the cell cycle?
A few stages in which the cell cycle divides to make new cells
What does a cell do before it divides?
Grow in size
Increase the amount of sub cellular structures
Duplicate the DNA
What are chromosomes?
Long coiled up DNA molecules which carry genes
Where are the chromosomes found?
In the nucleus
How many copies are there made in mitosis?
2
What are the two new cells made in mitosis called?
Daughter cell
What is the original cell in mitosis called?
Mother/parent cell
The new cells formed in mitosis are identical or different to the parent cell?
Identical
Describe the steps in mitosis
The DNA doubles The chromosomes line up in the middle One set of chromosomes is then pulled to each end of the cell The cytoplasm and cell membrane divides Two new daughter cells are formed
Why are cells dividing by mitosis?
Growth, development and repair
What is differentiation?
The process by which a cell changes to become specialised for its job
When can most animal cells differentiate?
At an early stage
WHen can most plant cells differentiate?
At any point of time
What is the function of muscle cells?
Contraction
How are muscle cells specialised to carry out their function?
They have a lot of mitochondria for energy for contraction
They are long so have a lot of space to contract
Name types of specialised animal cells
Sperm, muscle and nerve
Name types of specialised plant cells
Root hair, xylem and phloem
What is the function of a nerve cell?
Send rapid signals to the brain
How is a nerve cell adapted to carry out its function?
It is long so it can cover a large distance
It is branched to form a large network of connections
What is the function of a sperm cell?
Reproduction
To carry the male genetic information to the female’s genetic information
How is the sperm cell adapted to carry out its function?
It has a long flagellum helping it to swim
Has a lot of mitochondria for energy to swim to the egg
Acrosome in the tip of the head contains enzymes that can break down the egg cell membrane
What is the function of the xylem?
Carry water from the roots to the rest of the plant
Is the direction of movement of water in the xylem upwards, downwards or in both direction?
Upwards only
What is the function of the phloem?
Transport glucose from the leaves to the rest of the platn
IS the transport direction nor glucose in phloem upwards, downwards or in both directions?
Both directions
How are the xylem cells adapted to carry out its function?
They are hollow
How are the phloem cells adapted to carry out its function?
They have few sub cellular structures so that glucose can flow through it more easily
Name two type of animal stem cells
In the adult bone marrow and embryonic stem cells
Where are the stem cells found in plants?
In the meristem
What can the embryonic stem cells change into?
Any kind of human cell
What can the adult bone marrow stem cells change into?
Most human cells
What can the plant meristem stem cells change into?
Any kind of plant cells
What are the risk of growing stem cells in a lab?
The stem cells can get contaminated with a virus which can be passed on to the patient
What are the uses of stem cells in medicine?
For Type 1 diabetes patients to form cells which can make insulin
For paralysed patients to make new nerve cells
What is therapeutic cloning?
Making an embryo that has the same genetic information as the patient and using its stem cells to treat the patient
What are the advantage of therapeutic cloning?
The stem cells will not be rejected by the patient’s body
What are the two types of passive transport?
Diffusion and osmosis
What are the properties of passive transport?
They don’t require energy and the particles move from a high to low concentration
Give an example of diffusion in an animal
CO2 and O2 in the lungs
And glucose from the blood to the organs
Define diffusion
Diffusion is the movement of particles from high to low concentration
Which type of molecules can diffuse?
Only small molecules such as CO2, O2 and glucose
Define osmosis
The movement of water molecules from a dilute to concentrated region
Which factors increase the rate of diffusion?
High surface area (+)
High temperature (+)
A high concentration gradient (+)
Why does a larger surface area increase diffusion?
There is more room for particle to move
Why does an increase in temperature increase diffusion?
The particles move faster (increased kinetic energy)
What is active transport?
Movement of particles against the concentration gradient using energy
Where does the energy needed for active transport come from?
From respiration
Give an example of active transport in plants
Mineral ions from the soil through the root hair cells
Give an example of active transport in animals
Absorbing glucose (for cell respiration) into the bloodstream from the gut
Do single felled organisms have a large or small SA: volume ratio?
Large
What do single called organisms depend on for their substance exchange?
Diffusion
Is diffusion only enough for multicellular organisms to carry out substance exchange?
No
Do multi cellular organism have a small or large SA:volume ratio?
Small
What do multicellular organism need to transport things in and out of the cell?
Exchange surfaces and transport systems
What are the four things that exchange surfaces all have in common?
A large surface area
A thin membrane
Good and efficient blood supply (animals)
Ventilation (in animals)
What is the function of a large surface area in exchange surfaces?
So that more diffusion can take place
What is the function of a thin membrane in exchange surfaces?
So that the particles can travel/diffuse over a shorter distance
Name four organs that are adapted for exchange
Alveoli (in lungs)
Villi in the small intestines
Gills (in fishes)
Leaves (in plant)
How are leaves adapted to substance exchange?
They have a flat shape
They are exchanging gases through the stomata Between the air and the leave
How are gills adapted to substance exchange?
They have a lot of thin surface layers of cells
They a lot of capillaries
They are exchanging gases between the water and blood
How are the alveoli adapted to substance exchange?
There a lot of of them (increase surface area)
They have thin membranes
They have blood capillaries around them
They are exchanging gases between the air and the blood
How are the villi (small intestines) adapted to substance exchange?
They are very thin
There are a lot of them
There is a lot of blood capillaries around them
They are exchanging food molecules from the gut/intestines into the blood
