What do chromosomes contain
They Contain Genetic Informations
What are Chromosomes
Cooled up lengths of DNA Molecules
Body cells Normally have 2 copies of each chromosomes what is this called and where are they from
They are called diploid Cells and 23 comes from your mother and the other 23 comes from your dad
What does the cell cycle do
Makes new cells for growth and Repair
The stage of the cell cycle when the cell divides is called what
Mitosis
What is mitosis used for
Used for growth and repair
Some organisms use mitosis to reproduce what is known as…
Asexual reproduction
What are the stages of the cell cycle
Interphase Prophase Metaphase Anaphase Telophase Cytokinesis
What happens during interphase
DNA is spread out in long strings and forms x shaped chromosomes , the cell makes copies of itself
What happens during prophase
Membrane around the nucleus break down
What happens during metaphase
Chromosomes line up at the centre of the cell
What happens during anaphase
Each chromosomes split in half and pulled to opposite ends of the cell
What happens during telophase
Membranes form around each new set of chromosomes
What happens during cytokinesis
Cytoplasms and cell membranes divide
What is growth
It’s an increase in size or mass
What does growth involve
Cell division, elongation and differentiation
All growth in animals happen by what
By cell division
Plants grow by what..
They grow by cell division and cell differentiation
What is Cell elongation
It’s when a plant cell expand making the cell bigger
Development in animals and plants happen by what…
Happens by cell differentiation
What is cell differentiation
How a cell changes to become adapted to its job
An organisms DNA controls what
How quickly cells divide by mitosis
What are percentile charted used for
Used to monitor growth
Cells differentiate (change) to be become what?
To become specialised cells
Undifferentiated Cells are called what..
Stem cells
Where can stem cells be found
They can be found in animal embryos called embryonic stem cells
What are embryonic stem cells important for
They are important for growth and development of organisms
Adult stem cells can only produce what..
Certain types of specialised cells
In animals what are adult stem cells used to replace
Used to replace damaged cells e.g. to make new skin cells
Plants have a tissue called what..
Meristems
What do meristems contain
Plant stem cells
Where are meristems found in
They are found in areas of a plant that is growing e.g. roots
What else are stem cells used in
Can be used in medicine
What is the nervous system made up of
Nerve cells (neurones)
What does the body have a lot of in the nervous system
Sensory receptors
What are sensory receptors
They are groups of cells that can detect a change in your environment
Fill in the Blanks
When a S_________ is detected by R___________
The information is C__________ to A N__________
I_________
1.Sensory
2.Receptors
3.Converted
4 Nervous Impulse
The nervous impulse from stimulus to receptors is sent along from where to where
Sent along sensory neurones to the CNS
Impulses Travel through the CNS along which neurones
Relay neurone
What do all neurones have
A cell body
Dendrites or dendrons
Axon
What are axon
Extensions that carry nervous impulses away from the cell body
Some axons are surrounded by a fatty material called what
Myelin Sheath
What is the function of myelin sheath
Speeds up electrical impulses
What is the function of the sensory neurones
Carries impulses from receptors to CNS
What is the function of motor neurone
Carries impulses from CNS to effectors
What is the function of the relay neurones
Carries impulses through the CNS
What is a Synapse
It’s where 2 neurones join together
When a electrical impulses reach a synapse what happens next
Chemicals called neurotransmitters move across the gap
What does neurotransmitters set off in the next neurone
They set off new electrical impulses in the next neurone
What are reflexes
Reflexes are automatic (they happen without you thinking)
This makes them quicker than normal responses
What do reflexes help stop doing and give an example
They help you stop injuring yourself e.g. move your hand from a hot iron
What is a reflex arc
It’s the passage of info in a reflex (from receptor to effector)
Where do the neurones in a reflex arc go through..
They go through the spinal cord or an unconscious part of the brain
Give an example of how a reflex arc would work
Bee stings your fingers
1) Bee sting detected by sensory receptors
2) impulses are are sent along a sensory to the CNS
3) In the CNS, Relay neurone passes on the impulses from sensory to motor
4) Impulses are sent along motor neurone to the effector
5) effector is a muscle. It contracts to move your hand away from the bee
