Topic 2 - Cells and Control

Interphase

Cell grows new organelles synthesised replication DNA

Prophase

Nuclear membrane disintegrates DNA unwinds and condenses spindle fibres visible

Metaphase

Chromosomes equator spindle fibres at centromere

Anaphase

Chromosomes pulled to the poles by spindle fibres

Telophase

Nuclear membrane forms around each set of chromosomes

Cytokinesis

Split of cytoplasm 2 separate diploid cells Genetically identical

How would animal cells cancer

Mitosis then differentation

How would plant cells cancer, tip of a root

Cell division by mitosis, elongation

Steps of cancer (4)

Oncogenes Ignores signals Uncontrolled cell division by mitosis cancerous cells not removed by immune

Oncogenes

cancer causing genes

Carginogens

Cancer causing agents

Where embryonic stem cells

Developing embryo

Example of totipotent cell

embryonic cell

Embryonic stem cells treat

Diabetes

Embryonic risks

Contamination with virus should they have rights expensive

Adult stem cell where (5)

Bone marrow skin liver brain umbilical chord

mulitpotent stem cells example

Adult stem cell

Adult stem cells produce (5)

Blood skin specific organ cells muscle nerve

Benefits of adult stem cells

No rejection no waiting lists

Risks adult stem cells

Cultured ones accumulate mutations

Meristems where

Tips of roots and shoots

Benefits of meristems

Clone crops to desired taste

Totipotent stem cell

Any cell

Pluripotent stem cell

Almost any cell

Multipotent stem cell

Limited ability

Cerebrum function (4)

Consciousness memory intelligence language

Hypothalamus function (2)

Homeostasis body temperature

medulla oblongata (2)

Unconscious activities: breathing heart rate

Cerebellum

Muscle coordination movement balance

Spinal chord function

Relays info to and from brain

CT scanners how

X-rays fired at brain

PET scanners how

Radioactive traces collect inc blood flow

(F)MRI scanners how

Strong magnetic field and radio waves

Sensory neurone

Sends call signals to CNS from sensory receptor cells

Relay neurone

Transmit electrical impulses form sensory neurone to the motor neurone

Motor neurone

From CNS relay neurone to the effector

Sensory receptors

Receives info and generates nerve impulses to the brain

Neurone

Sends and receives electrical impulses via spinal chord

CNS

Brain and spinal chord

Synapse

Allow signals to pass from one neurone to the next

Axon

A cable where electrical impulses travel away to be receives by a neurone

Dendron

Receive info from other neurones and transmit stimulation (branch-like)

Myelin sheath (2)

Allows electrical impulses to transmit quickly and efficiently insulate and prevent leaks

Neurotransmitter

Carries chemical signals from a neurone to a target cell

Reflex arc

Controls a reflex

An effector

Muscle/gland makes the response happen

The nervous pathway (6)

Stimulus Sensory receptor sensory neurone relay neurone motor neurone effector response

Nervous pathway, stimulus detected by

Receptor

Nervous pathway, sensory neurone sends...to...

Electrical impulses, spinal chord

Ciliary muscle

Changing shape of lens

Ciliary muscle with near object

Contract

Suspensory ligament (2)

Hold lens in place changing shape of lens

Iris

Regulates light entering pupil

Cornea

Refracts light rays

Conjunctiva

Protects eye surface

Pupil

Allows light to enter

Lens

Focuses light on retina

Lens when near object

Thick

Retina

Contains light receptors

Rods

Sensitive to light (dim)

Cones

Colour vision

Fovea

Area of retina provides clearest vision

Optic nerve

Impulses from eye to brain

Nerve (2)

Bundle of sensory neurones carry impulses to the brain

Sclera (2)

Tough outer layer extraocular muscles can attach to

Lacrimal gland

Lubricates and protects surface of the eye

Short sightedness because (2)

Eyeball too long cornea too curved

Short sightedness cornea

Bends light too much

Cornea where short sightedness

Front of retina

Long sightedness because

eyeball too short cornea not curved enough

Cornea where long sightedness

Behind retina

Colourblindness because

Cones

Cataracts because

Build of protein clouding of lens not sharply focused