Cells and Control Flashcards
What is produced in mitosis?
The mother cell produces two genetically identical cells to parent. It produces diploid cells. It produces body cells and is used for growth and repair.
What happens in interphase?
The DNA in the chromosome is copied ready for mitosis.
What happens in Prophase?
Chromosomes condense (coil-up tightly).
What happens in Metaphase?
The chromosome and their copies line up in the middle of the cell.
What happens in Anaphase?
The chromosomes are pulled away by spindle fibres to opposites sides of the cell.
What happens in Telophase?
The nucleus splits and two new nuclei (plural of nucleus) form.
What happens in Cytokinesis?
Before the end of telophase the cytoplasm and the cell membrane divide to make two separate cells.
Where are stem cells found?
In human embryos.
What is the function of the stem cells?
They are specialised to divide by mitosis to become new cells.
Where can stem cells be found in adults?
Bone marrow.
What are meristems specialised to do?
They produce unspecialised cells that can divide and then form any types of cells in plants. However, they can continuous generate any type of cell throughout the plants lifetime unlike stem cells.
Where can the meristems be found?
In the tips of the roots and shoots.
What can stem cells be used to cure?
It can sometimes be cure sickle cell anaemia with a bone marrow transplant.
What are the risks of using stem cells?
Tumour developments due to cells dividing quickly.
Disease transmission due to viruses living inside cells.
Rejection due to the body thinking it is a foreign cell leading to the immune system being triggered.
Ethical reasons due to people think they shouldn’t experiment on potential human life.
What are the benefits of using stem cells?
Can be used to replace damaged or diseased body parts. Unwanted embryos from fertility clinics could be used as they would otherwise be discarded.
What are the drawbacks of using stem cells?
Removal of stem cells results in destruction
of the embryo.
People may have religious or ethical
objections as it is seen as interference with
the natural process of reproduction.
What is the function of the cerebrum?
It is split into two halves known as the cerebral hemisphere. The right side controls the left side vice versa. It controls movement, intelligence, memory, language and vision.
What is the function of the cerebellum?
It controls muscle coordination and balance.
What is the function of the medulla oblongata?
Controls unconscious activities like breathing and your heart rate.
What is the function of the CT scan?
It uses x-rays to passes through the brain. It shows the main structures of the brain. It shows a diseased or damaged brain.
What is the function of the PET scan?
It uses radioactive chemicals to show what parts of the brain are active when they are inside the scanner.
What is our nervous system made up of?
Neurones
What is a stimulus?
A change in the environment which are detected by sensory receptors.
Describe when a stimulus is detected by receptors.
- the information is converted to nervous electrical impulses
- then sent along the sensory neurones to the CNS
- The CNS coordinates a response
- impulses travel through the CNS along relay neurones
- The CNS sends information to the an effector (muscle / gland) along a motor neurone
- The effector then responds accordingly
- The time it takes to respond to a stimulus is called your reaction time
What is the function of the axons?
Carry nerve impulses away from the cell body.
What is the function of the dendrites and dendrons?
Extensions that connect to the neurones and carry nerve impulses towards the cell body.
What is the function of the myelin sheath?
Act as electrical insulators that speed up electrical impulse.
What do the neurones look like?
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What connects two neurones?
Synapse
What is the process of nerve signals travelling?
- Nerve signals are transferred by neurotransmitters which diffuse across the gap
- The neurotransmitters set off a new electrical in the next neurone
- Transmission of nervous impulses are fast but is slowed down by the gap because diffusion takes time
How does reflexes work?
A receptor in the skin detects a stimulus (the change in temperature).
Sensory neurones send electrical impulses to relay neurones, which are located in the spinal cord. They connect sensory neurones to motor neurones.
Motor neurones send electrical impulses to an effector.
The effector produces a response (muscle contracts to move hand away).
Eye parts labelled
https://quizlet.com/gb/375171104/the-eye-edexcel-biology-gcse-9-1-flash-cards/
Cornea function
Refracts light into the eye
Iris function
Controls how much light enters the pupil
Lens function
Helps refracting light and focus light onto the retina
Retina function
Covered in receptors of cones and rods which detect light
What happens to the information from the light?
Converted into electrical impulses. Optic nerve carries the impulses from the receptor to the brain.
Ciliary Muscle function
Contract and relax when focusing light`
Describe what long-sightedness does?
- People are unable to focus on near objects
- Due to the eye being short it doesn’t bend light enough it doesn’t focus in front of the retina
- It can be fixed using convex lenses
Describe what short-sightedness does?
- People are unable to focus on distant objects
- The eyeball is too long that it cant focus in front of the retina
- It can be fixed using concave lenses
What causes colour blindness?
When the colour cones in the retina aren’t working. this causes some people to not distinguish between two colours.
What causes cataracts?
It is a cloudy patch on lens which stops light entering the eye normally. It is caused by a build up of a certain protein in the eye. It can be treated by replacing the lens with an artificial one.
How do you remember mitosis cycle?
I PMAT
What is the function of the sensory neurone?
To transfer signal from a receptor to the CNS
What happens to the circular and radial muscles when the pupil constricts?
- The circular muscle contracts
- The radial muscle relaxes
What are three way the brain can be studied?
- CT, PET and MRI scans
- electrically stimulate different parts of the brain using electrodes to see their functions
