Paper 1: Section 2- Cells and Control Flashcards
What are the differences between mitosis and meiosis?
Mitosis: Meiosis:
. Growth and . Gametes
repair
. Asexual . Reproduction
. 2 daughter cells . 4 daughter cells
. Diploid (46) . Haploid (23)
. Identical/ clones . Varied
What are the 6 stages of mitosis?
Interphase- DNA is copied
Prophase- the chromosomes pair up and the nucleus dissolves
Metaphase- chromosomes line up in the middle
Anaphase- spindle fibers pull chromosomes to the opposite sides
Telophase- a membrane forms around each set of chromosomes (2 separate nuclei)
Cytokinesis- two separate daughter cells form
What makes the stage of metaphase different in meiosis?
Dependant assortment
What is dependant assortment?
For any given pair lined in the center of the cell, there is one maternal chromosome and one paternal chromosome.
What is known as crossing over?
Segments of each chromosome, in a pair, attach themselves to the other.
What is the result of changes in the cell that lead to uncontrolled cell division?
Cancer
What happens to an unspecialised cell when it differentiates?
It becomes a specialised cell.
What is a tumour?
The lump of cells formed as a result of uncontrolled cell division.
A _______ tumour is not cancerous and cannot ______ to other areas of the body.
- benign
- spread
__________ tumours are fast-growing. They are _________ and can invade and spread to other areas of the ____.
- Malignant
- cancerous
- body
Describe the process called metastasis.
As the malignant tumour grows, cancer cells detach and can form secondary tumours in other parts of the body.
What are the chemicals and other agents that can cause cancer called?
Carcinogens
How do carcinogens cause cancer?
By damaging DNA, causing mutations to occur.
What is a mutation?
A random and spontaneous change in the structure of a gene, chromosome or number of chromosomes.
What is a common misconception about the growth of cancer?
A single mutation will not cause cancer. Several are required for this to occur.
List 5 lifestyle factors that are linked to cancer:
. Viruses like HPV
. The chemical carcinogens in cigarette smoke
. Alcohol intake
. Exposure to UV radiation, part of which is ionising,
. Fat and salt intake increases the risk of cancer
List 2 industrial and environmental factors that are linked to cancer:
. Exposure to ionising radiation increases the risk factor
. Exposure to chemical carcinogens
Name 7 specialised systems in animals.
- Circulatory system
- Excretory system
- Muscular system
- Nervous system
- Respiratory system
- Skeletal system
Name 5 specialised cells in plants.
- Palisade mesophyll
- Spongy mesophyll
- Guard cells
- Phloem Sieve tubes
- Xylem vessels
What is a zygote?
A fertilised egg cell.
What happens to an unspecialised cell when it differentiates?
It becomes a specialised cell.
What are the 3 following ways growth of babies are measured in?
- Mass (kg)
- Length (cm)
- Head circumference (cm)
What is a percentile growth chart?
A chart that is used to compare the growth of a baby to the growth of other babies.
What is an adult stem cell?
A type of stem cell found in specific locations in adults that can only differentiate into a limited number of related cell types.
What is an embryonic stem cell?
A type of stem cell found in the embryo, capable of dividing into almost any cell type.
Finish the sentence: Bone marrow cells, being adult stem cells, can differentiate into…
blood cells and cells of the immune system, but not other cell types.
The main meristems are close to the tip of the ____, and the tip of the ____. Cells of the meristem can ____________ to produce all types of plant cells at any time during the life of the plant.
- shoot
- root
- differentiate
Name 3 instances where stem cells could be used to replace cells that have been damaged or destroyed:
. With type 1 diabetes
. In cases of multiple sclerosis
. In cases of spinal cord or brain injury
What are the benefits of using stem cells?
Stem cells have the potential to treat a wide range of diseases and injuries. They can be used to replace damaged cells, regenerate tissues, and even cure certain medical conditions.
Name 3 medical conditions stem cells can be used to treat.
. Diabetes
. Parkinson’s disease
. Heart disease
What are 3 risks associated with stem cell therapy?
. There is a risk of rejection by the body’s immune system
. A risk of the stem cells turning into cancer cells
. The long-term effects of stem cell therapy are still unknown, so further research is needed.
What is the brain and its function?
Its part of the CNS,controlling complex behaviour.
What is the function of the cerebellum?
It controls movement such as balance, coordination, muscles and movement.
What is the function of the medulla oblongata?
Involved in unconscious control like heart rate, breathing, and producing adrenaline.
What is the function of the pituitary gland?
Produces important hormones like FSH and LH.
What is the function of the hypothalamus?
Involved in homeostasis, maintaing body temperature.
What is the function of the cerebral cortex?
Responsible for the higher-level processes of the human brain. This includes language, memory, thought, decision-making and emotion.
What is known as mapping the brain?
When research is done in the brain the aim is to ‘map’ the region of the brain to particular functions.
Name 4 facts on MRI scans:
. Magnetic fields/ EM waves
. Investigates activity + structure of the brain
. Safer than CT scans
. Shows lost ctive during various activities also
Name 4 facts on CT scans:
. X rays (ionising radiation)
. Investigates structure of the brain by producing images
. They can show damage
Name 4 facts on PET scans:
. Radioactive chemicals
. Highlights activity of the brain
. Help identify unusual activity
Name 4 facts on Electrical stimulation scans:
. Used to map areas of the brain
. Certain parts of the brain are stimulated nd the effect is observed
. EEGs are studies to observe this electrical activity
Why do we analyse brain damage?
. To understand the importance of specific parts of the brain
. Brain scans correlation with body functions
What are the risks of brain research?
. The tissues of the brain, spinal cord and other parts are intricate and delicate
. Certain damages may be hard to remove
. Brain surgery is dangerous
. Damaged neurones are hard to repair
Why can brain treatment be seen as unethical?
You may get informed (knowing it’s risk) consent from the individuals.
What is the nervous system?
The system that helps humans react to their surroundings and coordinate their behaviour.
CNS structure: What is the stimulus?
A change in environment.
CNS structure: What is the receptor?
Cell at start of the pathway, that detects the stimuli.
CNS structure: What is the coordinator?
The CNS coordinates a response.
CNS structure: What is the effector?
Effect the response (a muscle or a gland).
CNS structure: What is the response?
The outcome.
What does a neurone do?
Carry electrical impulses.
What are nerves made up off?
Neurones/ nerve cells
What are the 5 properties of neurones?
. Axons
. Myelin sheath
. Cell body
. Dendrons
. Synapses
What does a sensory neuron do?
Send messages from the receptor to the coordinator.
What does a motor neuron do?
Sends messages from coordinator to the effector.
What does a relay neuron do?
Connects the sensory and motor neuron.
What is a synapse?
A junction between two neurons or a neuron and an effector cell.
What is the tiny gap between the cells at a synapse?
Synaptic cleft
What is a synaptic knob?
The presynaptic neuron ends that are swollen, which contain small vesicles neurotransmitters.
Neurotransmitters are ______________ messengers that transmit nerve impulses across the ________ gap during the process of synaptic ____________.
- electrochemical
- synaptic
- transmission
