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Biology > Unit 2 QCAA > Flashcards

Unit 2 QCAA Flashcards

1
Q

define disease

A

Any deviation from the normal structure or function of an organ/system

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2
Q

identify difference between infectious vs non-infectious diseases

A

Infectious - transmitted from one to another

Non-Infectious - caused by genetic and lifestyle factors

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3
Q

define pathogen

A

a causative agent of disease

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4
Q

define prion

A

type of protein that can trigger normal brain proteins to fold abnormally (cause neurodegenerative diseases)

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5
Q

define virus

A
  • make of DNA or RNA, coated with protein shell (capsid)

- depend on other cells to reproduce (NON-LIVING)

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6
Q

define bacteria

A

prokaryotic organisms (pathogenic bacteria cause disease)

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7
Q

define fungi

A

eukaryotic organisms that secrete enzymes to externally digest before absorbing the nutrients

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8
Q

define protists

A

eukaryotic organisms, usually dont cause disease, but there are some that are pathogenic parasites that infect organisms to reproduce

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9
Q

define parasite

A

organisms that live on or in another (host) and obtain nourishment at the expense of the host

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10
Q

identify and describe virulence factors

A

Adherence factors:

  • ability to adhere to host cells
  • bacteria resist physical removal by producing fimbriae or pili, non-fimbrial adhesins and biofilm-producing glycocalyx

Invasion factors:

  • ability of pathogen to enter host tissues, multiply and spread to other tissues
  • eg. secrete enzymes to break down collagen, hyaluronic acid (‘glue’ holding cells together) to enter

Capsules:

  • allow pathogens to resist host immune defence by preventing phagocytes from adhering to them
  • antibodies cannot reach surface of bacteria to bind, therefore cannot initiate phagocytosis

Toxins:
- damage host tissues and be either endotoxins or exotoxins

Lifestyle Changes:

  • change pathogenicity dependent on environmental changes
  • eg. viruses switch between lytic and lysogenic cycles
  • eg. fungal spores remain inactive until soil conditions become more favourable
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11
Q

identify modes of disease transmission

A
  • direct contact
  • body fluids
  • contaminated food/water
  • disease-specific vectors (eg. mosquitos carrying malaria)
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12
Q

describe recognition of self vs non-self

A
  • MHC markers on surface of host cells label as ‘self’, no not attacked by immune system
  • antigens on pathogens are recognised as ‘non-self’, because different from MHC markers on host cells
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13
Q

innate vs adaptive immunity

A 
Innate:
- general/non-specific
Adaptive:
- specific to certain antigen
- developed through life
- involves B and T lymphocytes
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14
Q

give examples of physical and chemical defences of plants against pathogens

A

Physical defences:
- waxy cuticle
- bark/woody stems
Chemical defences:
- production of toxins harmful to pathogen (eg. insecticide pyrethrin)
- production of defensins with antimicrobial properties

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15
Q

identify barriers of the innate immune response in vertebrates

A
  • skin, mucus, cilia, saliva, tears, gastric acid
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16
Q

explain the inflammatory system

A
  • immune cells go to site of infection
  • vasodilation –> more cells can get to infection
  • mast cells secrete histamine and prostaglandins (cause vasodilation and increase permeability of capillaries)
  • phagocytes engulf pathogen and display antigens
  • natural killer cells destroy infected host cells
17
Q

Explain Humoral Response (B cells)

A
  • effector B cells (plasma cells) - secrete specific antibodies to bind with antigen
  • memory B cells - when activated by antigen, divide rapidly to produce plasma cells to secrete antibodies
18
Q

explain the cell-mediated response (T cells)

A
  • helper T cells - activate B cells, phagocytes and cytotoxic T cells
  • Cytotoxic T cells (killer T cells) - destroy infected host cells with chemicals
  • Memory T cells - survive for many ears and very quickly create cytotoxic and helper T cells when exposed to pathogen again
19
Q

describe and give examples of passive and active immunity for both naturally and artificially acquired immunity

A

Passive - antibodies gained via placenta or breastfeeding (natural) or via antibody serum injection (artificial)
Active - natural exposure to pathogen (natural) or vaccination (artificial)

20
Q

identify factors that facilitate in the transmission of disease

A
  • local, national and global movement of humans
  • natural movement of animals via migration
  • via water and wind
21
Q

identify factors affecting immunity (within pathogen and community)

A
  • persistence of pathogens within host
  • transmission mechanism
  • proportion of populated immunised (herd immunity)
  • mobility of individuals in affected population
22
Q

identify strategies to control spread of disease

A 
- personal hygiene measures (wash hands, masks)
Community level:
- contact tracing and quarantine
- school and workplace closures
- reduction of mass gatherings
- temperature screening
- travel restrictions
23
Q

describe homeostasis and how it is maintained

A
  • homeostasis maintained through feedback loops
  • feedback loops - recognise stimulus, receptors, control centre, effector, and communication pathways (hormonal and nervous)
24
Q

recognise the sensory receptors, and which type of stimuli they detect

A
  • mechanoreceptors (tough, pressure, hearing, equilibrium, position, acceleration)
  • thermoreceptors (temperature)
  • chemoreceptors (taste and smell)
  • nociceptors (pain, physical/chemical damage to tissues)
  • osmoreceptors (water volume)
  • photoreceptors (light intensity)
25
Q

explain catabolism vs anabolism

A

catabolism - break down molecules into smaller

anabolism - build up (synthesis) smaller molecules into larger

26
Q

explain why changes in metabolic activity alter optimum conditions for enzymes

A
  • metabolic activity produces heath and CO2 - affect pH levels
  • higher temps and extreme pH denature enzymes
27
Q

identify types of nerve cells

A
  • sensory (detects stimuli, sends internal or external sensory information to CNS)
  • interneuron/relay neuron (in CNS, link sensory and motor, in brain to process info)
  • motor neurons (carry impulses from CNS to effectors –> muscles or glands)
28
Q

differentiate between sensory and motor neuron structure

A

Motor:

  • soma at one end
  • dendrites connect directly to soma
  • longer axon
  • axon connects to effector

Sensory:

  • soma in centre of cell
  • dendrites connect to ends of axon
  • shorter axon
  • axon connects to receptor
29
Q

explain the process of passage of nerve impulse (action potential, and synapse transmission)

A

Action Potential:

  • resting potential at approx. -70mV, inactive and polarised (sodium on outside, potassium inside - negative inside overall)
  • when stimulated, membrane increases Na+ permeability, Na+ floods into cell, neuron briefly depolarised
  • if reaches threshold limit (-55mV), more Na+ enters
  • once action potential reaches around +30 - +40mV, Na channels close, neuron repolarises with inside becoming more negative again
  • hyperpolarisation - when repolarising, becomes slightly too negative before returning to resting potential
  • refractory period - time when neuron is repolarising, cannot generate another action potential

Synaptic Transmission:

  • action potential stimulates neurotransmitters contained in capsules in the synaptic knob to fuse to presynaptic membrane and diffuse across synaptic cleft through exocytosis
  • neurotransmitters bind to receptors on postsynaptic neuron, triggering new action potential
30
Q

describe hormones

A
  • chemical compounds that act as intercellular messengers to regulate various metabolic functions
  • relay messages to cells displaying specific receptors for each hormone
  • travel through circulatory or lymphatic system
31
Q

explain cell’s sensitivity to specific hormone

A
  • cell can change the concentration of specific hormone receptors on its membrane
  • upregulation - when hormone concentration in low, cell increases concentration of receptors on surface
  • downregulation - when hormone concentration is high, cell decreases concentration of receptors on surface
32
Q

describe signal transduction mechanism in hormonal system

A
  • hormone binding to receptor activates signal transduction

- signal transduction alters cellular activity (change permeability of membrane, alter gene expression)

33
Q

define endotherms vs exotherms

A

endotherms - heat produced and temp maintained internally, not reliant on external environment
exotherms - body temp dependent on external environment

34
Q

identify thermoregulatory mechanisms of endotherms (structural features, behavioural responses, physiological mechanisms, homeostatic mechanisms)

A

Structural Features:

  • brown adipose tissue (turn food into body heat by non-shivering thermogenesis)
  • increased no. mitochondria per cell (release more metabolic heat)
  • insulation (fur, feathers or fat layers)

Behavioural Responses:

  • kleptothermy (sharing of metabolic thermogenesis with another animal - huddling)
  • hibernation (slow metabolism, breathing, drop temp to conserve energy in winter)
  • aestivation (state of lowered metabolism and dormancy similar to hibernation, but in summer, not winter)
  • torpor (hibernation, but shorter periods, sometimes just through night or day)

Physiological Mechanisms:

  • vasomotor control (vasoconstriction or vasodilation in peripheral blood vessels)
  • Evaporative heat loss
  • Countercurrent heat exchange (heat transferred from warmer artery blood to colder venous blood from limbs
  • Thermogenesis/metabolic activity (shivering creates energy from ATP, or non-shivering with more mitochondria to create heat energy)

Homeostatic mechanisms:

  • increase certain hormones to affect metabolism
  • insulin increases glucose in cellular respiration, creating energy
35
Q

define osmoconformers vs osmoregulators

A

Osmoconformers - isotonic with salinity of environment, do not regulate salt and water concentration themselves
Osmoregulators - actively regulate salt and water concentration, independent of environment

36
Q

Identify osmoregulatory mechanisms (structural features, behavioural responses, physiological mechanisms, homeostatic mechanisms)

A

Structural features:
- animals have differing lengths of loop of Henle

Behavioural responses:

  • drink more when dehydrated
  • move to shade

Physiological mechanisms:
- specialised cells in gives can actively absorb or secrete salts (aid in moving between fresh and salt water)

Homeostatic mechanisms
- ADH increases reabsorption of water, making urine more concentrated (increase ADH when dehydrated, decrease ADH when too much water)

37
Q

identify osmoregulatory mechanisms in plants (based on environments)

A

General:

  • waxy cuticle on upper and lower epidermis
  • abscisic acid (ABA) produced in roots when soil is dry and translocated to leaves –> close stomata to reduce water loss

Hydrophytes (aquatic):

  • little need for support or transport tissue
  • water absorbed through leaves
  • waxy cuticle to repel excess water, not to prevent evaporation

Halophytes (salt water):

  • glands to actively secrete/remove salt
  • root level exclusion (roots structured to exclude 95% salt in soil)
  • tissue partitioning (concentrate salts in certain leaves which then fall off)

Mesophytes (only moderate water needed):

  • large root masses
  • leaves - broad, thin, waxy cuticle
  • most stomata on underside
  • produce abscisic acid

Xerophytes (dry conditions):

  • leaves - small, hard, thick cuticle, sunken stoma
  • fine hairs trap humid air, decrease evaporation
  • deep root system to reach water table

Biology (5 decks)

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