Topic 2 Using Spec Flashcards
(36 cards)
Describe cancer as the result of changes in cells that lead to uncontrolled cell division
When the cell goes through a mutation it can lead to uncontrolled cell division and new cells are produced even when the body does not need them. A group of cancerous cells produce a growth called a tumour
What is the zone of elongation
Further up the root and its where new cells grow in size
What is the zone of differentiation
Even further up the root and where new cells differentiate
Cell differentiation in plants
Many plants keep their ability to differentiate throughout their life therefore plants are always able to create new tissues
Differentiation in animals
Cell differentiation is rare in mature animals
Their cells mostly divide in order to replace cells and repaired tissues
New tissues are rarely created
What are plant stem cells
Found in the meristem tissue and can differentiate into all type of plant cell throughout the life of the plant. This allows plants to grow for their whole lives
What do stem cells in embryos do
Differentiate into most cell types to produce all the cell types that will make up the organism
What does a percentile chart show and how
Whether the baby is growing as they should be
The baby’s age (x-axis) and weight (y-axis)
If a baby is in the 1st percentile, 99% of all other babies at that age are heavier.
What can stem cells be used to do
Replace damaged cells that cause diabetes
What is therapeutic cloning
a process that produces (creates) an embryo with the same genes as the patient.
Stem cells taken from this embryo will have the same DNA as the patient. This means that the patient’s body will not reject the stem cells or body cells made from the embryo’s stem cells.
What are some disadvantages of using stem cells in medical treatment
.Stem cell transplantation could transfer viral infections
.ethical beliefs - killing an embryo is bad
. Rejection - introducing stem cells into a patient could cause the patient’s immune system to reject and destroy the new cells.
What is the brains function
The brain is made up of millions of interconnecting neurones (nerve cells).
Different regions of the brain are responsible for coordinating (organising) different functions.
Why is it hard to treat brain problems
As the brain is only partially understood
What is the function of the cerebellum
Responsible for muscle coordination and is important for movement, posture, balance and speech
What is the function of the medulla oblongata
Responsible for unconscious activities such as breathing and heartbeat
What is the function of the cerebral hemispheres
responsible for conscious thought (e.g. memory, language and intelligence).
How can we overcome the difficulties of of accessing brain tissue inside the skull
With the use of CT scanning and PET scans
How do CT scanners show the brains functions and identify tumours
Lots of x-rays are taken of the brain, and a computer then builds a 3D image of the brain’s structure.
Different types of cells absorb different amounts of the x-rays.
Brain tumours show up as white blotches.
How do PET scanners investigate brain functions
Using radioactive glucose, the amount of glucose different parts of the brain are using up can be detected.
An image of brain activity is then made.
Limitations of treating brain tumours
Treated with chemotherapy, radiotherapy or Brain surgery however these also cause lots of damage to the body
Limitations of spinal injury
If the spinal cord is severed (cut), electrical impulses can no longer travel to the brain.
Wires can partly re-connect the spinal cord, but this isn’t very effective.
What do neurones do
Carry electrical impulses between receptors
What is a synapse
Gaps between neurones
Describe synapses in the transmission of electrical impulses
The electrical impulse reaches the end of the neurone before the synapse.
This triggers the release of chemicals called neurotransmitters.
The neurotransmitters diffuse (move down a concentration gradient) across the synapse.
The neurotransmitters bind to receptors on the next neurone.
The presence of the neurotransmitter causes the production of an electrical impulse in the next neurone
