Topic 2- Cells and Control Flashcards
What is mitosis + what is it for?
x3
- Cell division and replication
- Repair, Growth, reproduction
Where does Mitosis take place?
Nucleus
What are the stages of a cell cycle?
-Interphase
-Prophase
-Metaphase
-Anophase
-Telophase
-Cytokinosis
What occurs in interphase?
-Longest period of time
-Cell grows, replicates DNA
-Chemical reactions take place
-Creates new organelles e.g mitochondria/ ribosomes double
What is Interphase?
And how much time to cells spend in it?
- 90%
- Longest period of time
-Cell grows
-replicates DNA
-Chemical reactions take place
-Creates new organelles e.g mitochondria/ ribosomes double
When does the membrane around the nucleus break down?
- Late prophase
What is Prophase?
- Chromosomes condense and become visible
- Membrane around the nucleus breaks down
(in thier little pairs)
What is Metaphase?
-Chromosomes line up in the equator of the cell
One chromatid either side
What is Anophase?
- Spindle fibres
- Pull the chromatids to either side of the cell
What is Telophase?
-New membrane formed around chromasomes at each end of the cell
new nucleus
What is Cytokinosis?
-The cell cytoplasm divides
-Leaving two genetically identical duaghter cells
Why is mitosis important in growth, repair and
asexual reproduction?
- Cells create new identical cells
What is cancer?
- Changes/ mutations in cells
- Cuase rapid and uncontrolable cell division
What are stem cells and why is differentiation important?
-Stem Cells divide and differentiate into specialised cells
-Need cells to perform different specialised functions
Muscle cells, nerve cells
How do plants grow?
3 words
-Cell division
-Elongation
-Differentiation
By meristems, the tip
Where does cell division take place in a plant?
-Tip
-Meristems
What is elongation and where does it take place in plants?
- Further back than meristems
- Become longer
meristem cells produce auxins, cuase receptors to allow hydrogen into cells
Lowers pH, activates enzyme to break hydrogen bonds between cell wall
Allows flexibility for cell to change/ elongate0-
Do plants or animals maintain embryonic stem cells all their life
Plants
What are embryonic stem cells and where are they in animals?
- Differentiate into any cell
- Found in embryos
Against/Risks associated with using embryonic stem cells
-Ethical (embryo, could be a human)
-Hard to come by (only embryo of animals)
-Catch a disease before implanted in body
-May become cancerouse (divide rapidly)
-Body may reject it (immune supressers used, more suseptible to disease)
What stem cells in animals are not only found in the emrbyo for?
Differentiation into Blood
e.g White/red blood cells or plasma
Where is the cerebellum?
The back of the head just above the spinal cord
What is the cerebellum for?
-Balance
-Muscle coordination
-Music
Where are the cerebral hemispheres?
Either side of the main part of the brain
x5
What do the cerebral hemisphere’s do?
-Control opposite side of the bodies movements
-Consciousness
-Intelligence
-Memory
-Language
Where is the medulla oblongata?
-Bottom middle
What does the medulla oblongate control?
-Unconsious activity
-Breathing rate
-Heartrate
-Blinking
How does a CT scanner work?
- X rays passed in all directions
- Absorbed and transmitted by different parts of body
-Produces image slices which are made into images by computers
Better at finding damaged areas
How does a PET scan work?
- Patien absorbs radioactive glucose
- Emmits gamma rays annihilation
- Areas that are used more (or cancerous) respire more and therefore absorb more of the glucose
- Scan picks up which places emmit more gamma rays (being used more)
Better for discovering underlying activity
How does electrical stimulation of the brain work?
for reaserch
- Skull opened
- Electrodes inserted (into the cerebral cortex)
-Part of brain stimulated to see response of patient
Why is it diffuclt to treat damage in the brain?
-Hard to reach (encased in skull)
-Has delicate surrounding brain tissue
Why is it diffuclt to treat damage in the spinal cord?
-No adult stem cells can differentiate
-Hard to acces as protected by the spine
Why is it diffuclt to treat damage / brain tumours?
-Divide rapidly
-Radio and chemo therapy can kill cancer cells but also harm healthy cells
-BLOOD BRAIN BARRIER limmits drug delivery to the brain
What is a reflex arc?
nerve pathway for unconscious actions
What is the structure of a sensory neutron?
-Receptor Cell
-Mylein sheeth covered axon
-Cell body
-Axon
What does a sensory neuron do?
Recieves stimuli (from outside body) and sends info to relay neurone
What does the dendtrites do?
Recieve information
What do axons do?
Transmit information
What is the axon terminal for?
-Transmit message to other cells
What does the relay neurone do
allow sensory and motor neurons to communicate
What is the Motor neurone’s structure?
-Dendtrites attached to cell
-Axon
-Axon terminal
Where are synapses in a neurone?
-In between one neurones axon and the others dendrite
-its a GAP
-Neurones do not touch
What is are the two neurones that sandwich the synpase called?
Presynaptic
Postsynaptic
How do synapses work in reflex arc?
2)Presynaptic release neurotramsitters (chemical messengers)
3) diffuses across synapse (20nm)
4) Binds with receptor in postynaptic membrane
5) Stimulates a new nerve impulse
What are the junctions between the synapse called?
synaptic cleft
Where is the cornea and what does it do?
-Transparent covering at front of eye
-Directs light rays into the eye and helps it focus onto the retina
Where is the lens and what does it do?
-Behind the iris (middlish frontish)
- Refracts light so it hits retina
Where is the pupil and what does it do?
-Black hole at front centre
- Allows light into the eye
Where is the iris and what does it do?
-Behind the cornea infront of the lens
-Controls pupil size
Where is the cilary muscles and what does it do?
- Attached to lens
- Control lens shape
Where is the retina and what does it do?
-Back of eye, first layer
-Contains light receptors
-Rods detect light intensity
-Cones detect colour/wavelength
Where is the optic nerve and what does it do?
-Back of eye (stem looking)
-Sends impulses to the brain
Where are the suspensory ligament and what do they do?
-Between lens and cilary muscles
-Fibres attach the two above
How much does the cornea refract for viewing near objects?
Very little
How much does the lens refract for viewing near objects?
More than cornea
How do we view near objects?
- Cilary muscles contract
- Suspensory ligaments relax
- thick round lense
How do we view far objects?
- Cilary muscles relax
- Suspensory ligaments contact
- Flatter, longer lens
What is fovea and its function?
-Small dent in retina
-Has Cones
Do cones work better in light or dark?
light
What do cones do?
- Detect wavelength of light
- The colour
What do rods do?
Detect light intensity
processed in black and white
How are rods and cones arranged?
-Cones in the centre
-Rods more surrounding
What colours can the cones detect?
Green, Red, Blue
What is the virteous chamber
-Thick viscous
-Maintains eye shape
How does the pupil change in bright light?
-Circular muscles contract
-Radial muscles relax
-Pupil becomes smaller
less light let in
How does the pupil change in darkness?
-Circular muscles relax
-Radial muscles contract
-Pupil enlargens
more light let in
What is cuases short sightedness?
-Light focused infront of retina
-Eyeball is too long/cornea too curved
What is cuases long sightedness?
-Light focused behind of retina
-Eyeball is too short/cornea too flat
How can short sight and long sight be fixed?
-Corrective lens
-Eye surgery (cutting cornea to reshape it)
What type of lens for short sight?
-Concave (tree)
What type of lens for long sight?
Convex (oval)
What cuases cataracts
Protien build up
What do cataracts cuase
cloudy vision
How are cataracts fixed?
fualty lens replaced with plastic one
What cuases colour blindess?
-Genetic disorder
-Passed by females (X chromosomes)
Why are men more likely to be colour blind?
- Girls need both X chromosomes to be fualty
- Boys only need one X chromosome to be fualty
(XX) (XY)
