Topic 2- Cells And Control Flashcards
What are the stages of mitosis?
- Interphase
- prophase
- metaphase
- anaphase
- telophase
explain interphase
The DNA in chromosomes copies itself ready for mitosis.
The cell spends most of its life in this phase.
explain prophase
The DNA in chromosomes and their copies condenses to become more visible.
The membrane around the nucleus disappears.
explain metaphase
Chromosomes and their copies line up in the middle of the cell.
explain anaphase
Chromosomes and their copies are pulled to different ends of the cell.
explain telophase
New membranes form around the chromosomes at each end of the cell.
definition of mitosis
- Mitosis is a type of cell division
- where a diploid body cell copies itself and finally divides into two identical diploid daughter cells.
- The daughter cells are clones of each other
definition of cell differention
When cells express specific genes that characterise a certain type of cell
Eg.blood cells
definition of cell division
mitosis causes cells to divide
definition of cell elongation
Where a plant cell expands, making the cel bigger and making the plant grow
what is cancer?
Out of control mitosis where the cells don’t stop dividing
definition of meristems
Meristems are regions of unspecialised cells in plants that are capable of cell division.
Meristems make unspecialised cells that have the potential to become any type of specialised cell.
how can stem cells be used in medicine?
•to cure diseases
(Eg. Sickle cell anaemia, cured with a bone marrow transplant)
•to create specialised cells to replace damaged ones
definition of stem cells
Stem cells are cells that have not undergone differentiation.
A cell which has not yet become specialised is called undifferentiated.
what is the function of the cerebrum?
- Controls muscles
* the right side of the cerebrum controls muscles on the left side of the body and vice versa
what is the function of the cerebellum?
Responsible for muscle coordination and balance
what is the function of the medulla oblongata?
Controls unconscious activities such as breathing and your heart rate
what is a CT scan?
1) A CT scanner uses X-rays to produce an image of the brain.
2) A CT scan main structures the brain, but it doesn’t show the functions of them.
3) However, if a CT scan shows a diseased or damaged brain structure and the patient has lost some function, the function of that part of the brain can be worked out.
For example, if an area of the brain is damaged and the patient can’t see, then that area is involved in vision.
What is a PET scan?
1) They use radioactive chemicals to show which parts of the brain are active when the person is inside the scanner.
2) PET scans are very detailed and can be used to investigate both the structure and the function of the brain in real time.
3) PET scans can show if areas in the brain are unusually inactive or active, so they are useful for studuing disorders that change the brain’s activity.
E.g. in Alzheimer’s disease, activity in certain areas of the brain is reduced PET scans show this reduction when compared to normal brain.
what is a sensory neurone?
- One long dendron carries nerve impulses from receptor cells to the cell body, which is located in the middle of the neurone.
- One short axon carries nerve impulses from the cell body to the CNS
what is a motor neurone?
- Many short dendrites carry nerve impulses from the CNS to the cell body.
- One long axon carries nerve impulses from the cell body to effector cells.
what is a relay neurone?
- Many short dendrites carry nerve impulses from sensory heurones to the cell body.
- An axon carries nerve impulses from the cell body to motor neurones
definition of synapse
- Where two neurones meet there is a tiny gap called a synapse
- Information crosses this gap using neurotransmitters
definition of iris
The iris controls how much light enters the pupil
definition of lens
The lens refracts light, focusing it into the retina
definition of retina
The retina is the light sensitive part and it’s covered in receptor cells called rods and cones which detect light
definition of rods
Rods are more sensitive in dim light but can’t sense colour
definition of cones
Cones are sensitive to different colours
definition of optic nerve
The optic nerve carries impulses from the receptors to the brain
definition of long sighted
- long-sighted people are unable to focus on near objects
- This occurs when the lens is the wrong shape and doesn’t bend the light enough or the eyeball is too short.
- Light from near objects is brought into focus behind the retina.
- You can use glasses or contact lenses with a convex lens to correct
definition of short sighted
- Short-sighted people are unable to focus on distant objects
- This occurs when the lens is the wrong shape and bends the light too much or the eyeball is too long.
- Light from distant objects is brought into focus in front of the retina
- You can use glasses or contact lenses with a concave lens to correct it.
