Biology

U2

What are the six board steps in a negative feedback loop

stimulus, receptor, relay, effective, response, and feedback

What is the difference between a positive and a negative feedback loop?

• a positive speeds up/amplify the reaction. for example when Apple releases a gas to signal other apples quickly ripen.

• A negative includes slowing down or stopping a reaction. For example, example sweating to reduce body temperature.

What are the five receptors?

nocireceptor → pain

photoreceptor → light

chemoreceptor → chemical compounds

thermoreceptor → temperature

mechanoreceptor → pressure

What are the three types of neurons and what do they do?

• interneuron – connects neurons together

• motor neuron - transfers signals from the CNS to tissues

• Sensory neuron - sends signals from the tissues to the CNS

What are the three steps of signal transduction when I hormone sends a signal to the cell?

reception – would detect hormones and binds to the cells outside receptor

Transaction – relays and converts a signal

Response – which either activates or deactivate the cellular activity

Relationship between increase and decrease and glucose

• when the glucose decreases the pancreas releases glycogen which the liver then breaks down into glucose. This is released into the bloodstream to increase the levels of glucose.

• When the glucose levels increase the pancreas releases insulin which triggers the uptake glucose and muscles and organs. This decreases the levels of glucose.

Which are the neuron characteristics? what does each do?

• Dendrite – detect or receives information or signals from other neurons or the external environment

• The nucleus – stores DNA and information

• The soma body maintains the life of the cell

• The axon - the pathway which the signal travels down. The axon also converts the signal into an electrical impulse

• Myelin Sheath – insulate the axon and speeds up the process of the electrical impulse

• Axon terminal - convert the electrical impulse back into a signal and connect and send it to other neurons.

Identify the four behavioural mechanisms and each use to reach Osmoregulation also what does each do?

• Kleptothermy - sharing of body temp

• Hibernation - reducing body temp and metabolic rate during winter

• Aestivation - reducing body temp and metabolic rate during summer

• Torpor - short-term state of reducing metabolism and activity

describe the feedback control of the thermoregulation

• as the temperature increases the hypothalamus receives a message to trigger the body to vasodilation and sweating to decrease body temp and return to homeostasis

• when the temperature decreases the hypothalamus receives a message to trigger the body for to Shiver to increase the body temperature and return back to homeostasis state to Shiver to increase the body temperature and return back to homeostasis state

Describe the structural mechanisms endotherm's use to achieve thermoregulation?

• Insulation - thick layer of fur or feathers which insulate animal’s from the external environment

• Brown Adipose tissues - a type of fat which produces heat through metabolising healthy fats

what is homeostasis?

• The maintenance of an internal stable environment whilst the external environment changes

what are the structural features to help plants with Osmo regulation and what do they do?

Stomata - regulates water movement by increasing your decreasing the loss of water

Vacuole - stores water and nutrients

Cuticle - thick sticky and waxy layer preventing the loss of water

Abscisic acid - suppresses the growth and closes the stomata to reduce water loss

what determines a cells sensitivity to a hormone?

• the number of receptors

• A high number of receptors = high sensitivity

• A low number of receptors = low sensitivity

what are the six type of pathogens?

• Virus

• Fungi

• protozoa

• prion

• bacteria

• parasite

what is the difference between an infectious and non-infectious disease? include examples - how it is caused?

• a infectious disease is a contagious disease which can be easily transmitted from one person to another. this often include infections such as a cold

• A non-infectious disease is a non-contagious disease. I cannot be transmitted from one person to another. These often include genetic and environmental factors for example cancer.

what are the 4 virulence factors and describe each

A capsule – is a protective coat which prevents the germ from the white blood cells

Adherence factors – a sticky structure to allow pathogens to stick to other cell

Toxins – harmful chemicals produced by pathogens which disrupt body functions

Invasive factors – is a specific chemical or enzymes which breaks down barriers to enter a host

What are the full modes of transmission and provide an example for each?

• Vector – being bitten by a mosquito

• Direct contact – touching contaminated food

• Bodily fluid contact – being coughed on

• Water/food contamination – food poisoning

Outline the physical and chemical defence in the inmate immune system in plants

physical structure - cell wall, cuticle and stomata

chemical - toxins

Distinguish between humoral and cell mediated immune responses

• Humoral - B-cells which produce and send out antibodies when it detects invaded pathogens outside the cell.

• Cell-mediated - T cells attach and kill the pathogen when it detects an invaded pathogen inside the cell - as antibodies can not detect them when it is inside the cell

What factors contribute to the persistence of a pathogen?

• Virulence factors

• toxins

• reproduction rates

• incubation period

Describe how quarantining hygiene and contact tracing help prevent the transmission of an infectious disease

quarantining – isolates the infection, preventing the spread from one person to another

hygiene – PPE, sanitise and washing hands prevent spreading

Contact tracing –text and informed individuals who may have come to contact with the infected individual. This allows them to isolate and prevent further spread of the disease.

what is a herd immunity?

a large group of people or a population of people are immune (vaccinated) to a specific disease. This prevents

What are the 4 types of immunity? and what does each do?

• Natural active - Produces antibodies after first encounter

• Natural passive - antibodies received in womb by mother

• Artificial Active - antibodies after a medical intervention (vaccine)

• Artificial passive - recieving antibodies straight into blood (anti-venom)

What is immunological memory, what is it produced by and why?

after the primary immune response, the B andT cells produce memory for a quicker response if the same pathogen invades again

what does the nervous and endocrine system do in the feedback loop?

• The systems uses the negative feedback loop response system.

• however after a change is detected, during the coordination section the nervous system sends rapid electrical impulses

• whilst the endocrine system triggers the hormones.

what are nodes of ravier?

Nodes of ravier are small, uncovered gaps in the axon they increase the speed of the signal which jumps from one gap to the next – saving energy.

what are synapes?

 

Synapses – located at the end of a axon and connects the axon to another axon’s dendrites creating interneurons

transduction proccess (4 steps)

An action potential travels down the axon to the synaptic cleft.

This triggers synaptic vessels to fuse with the membrane and release transmitters into the synaptic cleft.

The transmitter chemicals then float onto the postsynaptic neuron receptors and begin the process of signal transduction.

where are hormones produced? where do they travel to and why?

Hormones are secreted from the endocrine glands into the bloodstream to travel to target cells which contain specific receptors.

The lipid-soluble hormones can travel through the dissolve in fats to travel to the centre of the cell to alter genes.

Whilst water-soluble hormones can not dissolve in fat instead sticking to the cell’s outside receptors.

what are the 4 changes in cellular activity?

• due to hormones binding to target cells and altering its shape,

• sensitivity,

• up regulation (increases hormones receptors),

• down regulation (decreases hormone receptors)

What are the three physiological mechanisms and what does it do and how?  

• maintain homeostasis of temperature,

• Evaporative heat loss (sweat evaporates),

• vasomotor control which is the control of blood vessels (vasodilation – blood vessels widen to release heat when hot and vasoconstriction– blood vessels narrow when cold to trap heat)

• Thermogenesis and physical or biological forms to remain warm.

what is Osmoregulation?

balancing the concentration of water and salt levels within the blood.

what do Kidney’s filter?

water, salt and blood

what is ADH? what happens when it increases and decreases?

chemical message from hypothalamus to trigger the kidney to save water.

 

Low water levels = more ADH

High water levels = less ADH.

what are the 4 types of plant environment? what does contain?

 

-              Mesophytes – plants adapted to survive in moderate level water

-              Hydrophytes  - plants adapted to survive in full level water

-              Xerophytes - plants adapted to survive in extremely dry environments

-              Halophytes - plants adapted to survive in extremely salty environments

what are the key features of the 6 pathogens?

 

-              Prions – protein

-              Viruses – protein coat

-              Bacteria – prokaryotic and no nucleus  

-              Fungi – chitin cell walls

-              Protozoa – eukaryotic and nucleus

-              Parasites – living inside of outside of something

how do host cell distinguish between self and non-self?

 

Host cells use markers to recognise self and use antibodies to recognise non-self’s

what are the three lines of defence?

First line of defence – skin and mucus prevents pathogens invading

Second line of defence – white blood cells, proteins and inflammatory response destroy the pathogen by isolating it and killing it

Third line of defence – B and T cells

what is the Inflammatory response?

Inflammatory response – triggered by injury or infection which signals immune cells to destroy foreign invaders and clean up damage.

what do Prostaglandins?

Prostaglandins – trigger leakage of blood vessels to signal pain to heat the body up - inflammatory response

what does the inmate immune system consist of? what does each do?

Neutrophils – responds first to infections swallows and kills bacteria

 

macrophages – remove dead cells and germs

 

Natural killer cells – detects and destroys cells