Science Biology Unit 1 Year12 Flashcards
Explain how to use a microscope
first put the low power objective lens in place , then place the slide on the stage (then clip) , next adjust the light to full brightness and adjusting the coarse focus wheel , finally using the fine focus wheel to get a clear picture.
Define L-dopa
precursor of dopamine , goes into the brain
Explain how L-dopa treatment works
converted into dopamine by dopa decarboxylase (enzyme in the brain) , temporarily reduces motor symptoms by increasing dopamine to normal levels , however , only 5-10% of L-dopa is administrated in the brain , effectiveness is reduced as more brain cells die off.
Define and explain function of Golgi apparatus
membrane bound organelle found in most cells , responsible for packaging proteins into vesicles prior to secretion , plays a key role in secretory pathway
Define and explain how arteriosclerosis develops
blood vessels become thick, blocked by fat restricting blood flow to the rest of the body, high blood pressure and CO damages the inner lining of arteries and then growth of cholesterol
What is nervous tissue made out of?
neurons
Explain the function of neurons
receive and facilitate nerve impulses , action potentials across their membrane and pass it on to the next.
What are neurons made out of?
Soma cell body , Schwann cell with myelin sheaths , the gap between each myelin sheath is a node of Ranvier , small projections called dendrites and axon (axon terminal at the end of one) separated from the dendrite of the next neuron by a synapse gap.
Explain how a nerve impulse travels
crosses a synapse in the form of a neuron transmitter , they diffuse across the synapse and initiate an action potential in the neuron on the other side. The pre-synaptic neuron ends up in a synaptic bulb were mitochondria/ATP is needed.
Where is a neurotransmitter stored?
temporary vesicles in a synaptic bulb that can fuse to the surface to release
Define and state symptoms of Parkinson’s disease
a genetic disease that affects the nervous system to not able to produce natural produce dopamine. For example, slow movement, speech problems, tremors when moving, poor balance.
Define dopamine
a chemical and neurotransmitter that helps smooth and normal movements.
Name the all muscle tissues
cardiac , smooth , skeletal
Explain cardiac tissue and where it is found
in the heart , contracts at a steady rate to make a heartbeat and is involuntary
Explain smooth tissue and where it is found
in organs e.g. stomach , bladder and is involuntary
Explain Skeletal tissue and where it is found
contracts in order to move bones, lots of mitochondria , made up of lots of myofibrils
Features of fast-twitch muscles?
more mitochondria , used in anaerobic exercises , quick release of ATP
Features of slow-twitch muscles?
less mitochondria , used in aerobic exercises , quick release of ATP
Explain two functions of plasmids in bacteria
carry DNA/genes, antibiotic resistance
Why do myelinated neurons conduct impulses much faster than non-myelinated neurons?
impulse jumps over areas of myelin
Explain the structure of myelin-sheath
a neuron that consists of fat containing cells which insulate the axon from electrical activity
Explain the features of a sperm cell
acrosome (head) contains a enzyme that aids in breaking through the outer egg cell membrane, contains mitochondria in the middle, tail helps with mobility
Explain the features of a egg cell
outer membrane which supplies protein to the egg, large cytoplasm and nucleus contains 23 chromosomes
Explain the features of a root hair cell
large surface area = increase rate of absorption of water/ions, cell membrane is partially permeable to water, short distance across cell walls to increase rate of diffusion
