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IB Bio > Chapters 6 & 11 > Flashcards

Chapters 6 & 11 Flashcards

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Biology 101 flashcards
1
Q

What are MHC?

A
  • all nucleated cells of the body possess unique and distinctive surface molecules that identify it as self
  • these self markers are called major histocompatibility complex molecules
  • function as identification tags
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2
Q

Define immunoglobulins.

A

antibodies that are large and Y-shaped

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3
Q

How do antibodies destroy pathogens?

A
  • agglutination
  • making them more recognizable to phagocytes
  • neutralising toxins of pathogens
  • bursting them by forming pores
  • preventing viruses from docking to host cells
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4
Q

How are T cells involved in the immune response?

A

They have antibody-like receptor proteins in their plasma membrane to which ONE SPECIFIC ANTIGEN CAN BIND

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5
Q

Describe an allergic reaction.

A
  • occurs whenever non-self substance that would not normally trigger immune response enters body
  • specific B cell encounters the allergen,
  • it differentiates into plasma cells
  • makes large amounts of antibody
  • antibodies attach to mast cell
  • antibodies attach to & activate mast cells
  • this triggers release of histamines
  • histamines can bind to membrane-bound histamine receptors & cause allergic symptoms
  • histamine causes vasodilation + leaking to allow faster blood flow to area of infection
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6
Q

Explain the production of monoclonal antibodies.

A
  • small mammal injected w/ one type of antigen
  • antibody-producing cells removed from spleen
  • plasma cells that produce antibodies are used
  • myeloma/tumour cells are fused w/ plasma cells to produce hybridoma cells
  • selection of hybridoma cells
  • hybridoma cells are cultured/grown in tissue culture/fermenter
  • hybridoma cells divide endlessly to produce desired antibody
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7
Q

Outline one application of monoclonal antibodies.

A
  • detection of hCG in pregnant women
  • hCG is a protein secreted by developing embryo & later by the placenta
  • monoclonal antibodies for hCG are attached to the urine strip
  • if hCG is present in blood, antibodies will detect this & strip will change colour
  • otherwise, test strip does not change colour
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8
Q

Outline how the ABO blood group system is based on presence/absence of glycoproteins in membranes of red blood cells.

A
  • these glycoproteins cause antibody production - they are antigens
  • A antigen - made by adding N-acetyl-galactosamine molecule to O antigen
  • B antigen made by adding galactose
  • individuals w/ specific blood types may be unable to receive transfusions from other blood types
  • recognizing the new blood cell as nonself

A blood: accepts A or O only
B blood: accepts B or O only
AB blood: accepts all blood types
O blood: accepts only O blood

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8
Q

Outline how the ABO blood group system is based on presence/absence of glycoproteins in membranes of red blood cells.

A
  • these glycoproteins cause antibody production - they are antigens
  • A antigen - made by adding N-acetyl-galactosamine molecule to O antigen
  • B antigen made by adding galactose
  • individuals w/ specific blood types may be unable to receive transfusions from other blood types
  • recognizing the new blood cell as nonself

A blood: accepts A or O only
B blood: accepts B or O only
AB blood: accepts all blood types
O blood: accepts only O blood

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9
Q

What are spermatogonia?

A

undifferentiated germ cells

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10
Q

What helps spermatids to differentiate into spermatozoa?

A

they become associated w/ Sertoli cells

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11
Q

What is a primary follicle?

A

composed of primary oocyte and a single layer of follicle cells around it that forms after the primary oocyte becomes arrested at prophase I

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12
Q

What is produced at the end of oogenesis?

A

an ovum (haploid gamete) & one polar body

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13
Q

Describe the structure of an egg.

A
  • outer layer of follicle cells (corona radiata)
  • zona pellucida (jelly-like layer) - protects the egg & restricts entry of sperm
  • plasma membrane
  • cytoplasm - contains droplets of fat & other nutrients needed during early stages of embryo dev.
  • nucleus (haploid) - contains 23 chromosomes that are passed on from mother to offspring
  • 2 centrioles
  • polar body
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14
Q

Describe the structure of sperm.

A
  • acrosome - contains enzymes that digest zona pellucida around egg
  • helical mitochondria - produces ATP by aerobic respiration to supply energy for swimming & other processes in sperm
  • tail - provides propulsion that allows sperm to swim up vagina, uterus, & oviduct until it reaches the egg
  • microtubules - in a 9+2 array - make the sperm tail beat from side to side to generate force that propels sperm
  • protein fibers - strengthen tail
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15
Q

Outline the process of sex-determination.

A
  • SRY gene is found on Y chromosome
  • codes for TDF (testis determining factor), a gene regulation protein
  • TDF binds to specific DNA sites to stimulate expression of genes for testis development –> MALE
  • gonads develop into testes
  • if SRY not present, gonads develop into ovaries –> FEMALE
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16
Q

Outline male sex organs.

A
  • testes = produce sperm in seminiferous tubules + testosterone
  • epididymis = sperm matures
  • van deferens = sperm transferred through this duct
  • seminal vesicle = mix alkaline fluid rich in fructose w/ ejaculate
  • prostate gland = mixes alkaline fluid rich in enzymes/lipids/minerals –> helps sperm to swim + neutralises acidity of vagina
  • urethra = tube through which sperm + urine exit
  • penis = has erectile tissues which becomes enlargened & hard allowing penetration of vagina
  • scrotum = holds testes at lower than core body temp.
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16
Q

Outline male sex organs.

A
  • testes = produce sperm in seminiferous tubules + testosterone
  • epididymis = sperm matures
  • van deferens = sperm transferred through this duct
  • seminal vesicle = mix alkaline fluid rich in fructose w/ ejaculate
  • prostate gland = mixes alkaline fluid rich in enzymes/lipids/minerals –> helps sperm to swim + neutralises acidity of vagina
  • urethra = tube through which sperm + urine exit
  • penis = has erectile tissues which becomes enlargened & hard allowing penetration of vagina
  • scrotum = holds testes at lower than core body temp.
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17
Q

Describe female sex organs.

A
  • ovaries = egg develops in ovaries, ovaries produce estrogen/progesterone
  • oviduct = pushes egg out of ovaries using cilia after ovulation + fertilisation occurs
  • cervix = where male sperm will pass through + baby passes through during labour; cervix dilates to provide birth canal
  • uterus = provides protection, oxygen, food, removal of waste products for fetus during pregnancy
  • vagina = stimulates penis to cause ejaculation
  • vulva = protects internal parts of female reproductive system
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18
Q

Discuss testosterone.

A
  • produced by Leydig cells in seminiferous tubules of testes
  • signals development of primary + secondary male characteristics
  • triggers male sex drive
  • acts on Sertoli cells in the testes and stimulates production of sperm
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19
Q

Discuss progesterone.

A
  • signals dev. of female primary + secondary characteristics
  • initially produced by corpus luteum in ovaries
  • later produced by placenta
  • helps to thicken/maintain endometrium lining
  • involved in development of breast tissue during pregnancy
  • prevents uterine contractions during pregnancy
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20
Q

Discuss estrogen.

A
  • secreted by corpus luteum, later by placenta
  • stimulates development of FSH receptors
  • at high levels, it stimulates LH secretion (which stimulates ovulation)
  • repairs uterus lining
  • increases number of oxytocin receptors to increase uterine contractions
  • fall in progesterone, rise in estrogen lead to labour/contractions
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21
Q

What secretes FSH & LH?

A

anterior pituitary gland

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22
Q

What secretes progesterone & estrogen?

A

ovaries (corpus luteum) & later on the chorion of the placenta

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23
Q

Examples of positive & negative feedback in menstrual cycle.

A

POSITIVE FEEDBACK: FSH stimulates secretion of estrogen by follicle wall, estrogen levels increase # of FSH receptors, so estrogen & FSH levels rise

NEGATIVE FEEDBACK: estrogen stimulates LH secretion; LH causes estrogen levels to fall

NEGATIVE FEEDBACK: corpus luteum secretes progesterone & estrogen, causing LH levels to fall (negative feedback since FSH & LH stimulated estrogen & progesterone secretion)

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24
Q

Define homeostasis.

A

the maintenance of stable internal conditions or environments / within narrow limits
- hormonal/nervous control
- negative feedback mechanisms
- monitored internally

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25
Q

What is negative feedback?

A

a change in one variable causes the other to change in the opposite direction

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26
Q

Where is leptin produced? What does it act on?

A
  • in adipose fatty tissue cells
  • leptin acts on receptor sites of hypothalamus
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27
Q

Outline how melatonin acts to control circadian rhythms.

A
  • ganglion cells in retina detect differences in light/dark
  • send impulse to supra-chiasmatic nuclei (SCN) in hypothalamus
  • neurons in SCN control secretion of melatonin by pineal gland
  • melatonin acts on hypothalamus –> sleepiness
  • this hormone is removed by liver
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28
Q

How does thyroxin increase body temperature?

A
  • increases metabolic rate
  • uncoupled cell respiration in brown adipose tissue
  • heat generation by shivering
  • hypothalamus in brain detects temp changes
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29
Q

Why is iodine important for synthesis of thyroxin?

A
  • thyroxin molecule contains 4 atoms of iodine
  • prolonged deficiency of iodine in diet prevents synthesis of thyroxin
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30
Q

How is the body cooled?

A
  • less thyroxin is secreted from thyroid gland
  • release of sweat by sweat glands
  • evaporation of water cools body
  • heat is transferred by blood
  • transfer of heat from body core in blood to surface via vasodilation of skin blood vessels
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31
Q

Which 2 organs are responsible for maintaining blood pH?

A
  • lungs - by exhaling CO2
  • kidney
32
Q

Distinguish b/w internal & external fertilisation.

A
  • external –> water required, timing is critical, lots of energy used, energy goes into producing many eggs, no parental care of offspring
  • internal –> water balanced in a dry environment, fewer eggs - protection for egg/embryo; complex organs & cooperative behaviour; parental care of offspring is high
33
Q

Outline features of steroid hormones.

A
  • derived from cholesterol
  • progesterone, estrogen, testosterone

FSH & LH ARE NOT STEROID HORMONES

34
Q

Distinguish b/w Type I & Type II diabetes.

A

TYPE I:
- childhood, genetics
- immune system destroys beta cells in pancreas so amount of insulin secreted is insufficient
- high levels of glucose in bloodstream
- treated by regular insulin injections

TYPE II:
- occurs later in life due to lifestyle factors
- beta cells become desensitised to glucose levels, preventing release of insulin
- insulin injections not enough
- diet must be healthy
- risk factors include diet rich in fat, low in fiber, obesity, lack of exercise

34
Q

Distinguish b/w Type I & Type II diabetes.

A

TYPE I:
- childhood, genetics
- immune system destroys beta cells in pancreas so amount of insulin secreted is insufficient
- high levels of glucose in bloodstream
- treated by regular insulin injections

TYPE II:
- occurs later in life due to lifestyle factors
- beta cells become desensitised to glucose levels, preventing release of insulin
- insulin injections not enough
- diet must be healthy
- risk factors include diet rich in fat, low in fiber, obesity, lack of exercise

35
Q

What is the function of circular muscle in peristalsis?

A

prevents backward movement of food

36
Q

What is the function of longitudinal muscle in peristalsis?

A

moves bolus food along the gut

37
Q

Function of lipase in digestion.

A

breaks down LIPIDS into FATTY ACIDS & GLYCEROL

38
Q

Define absorption.

A

the taking in of digested food substances as well as minerals and vitamins from the lumen of the small intestine into the blood

39
Q

Adaptations of the villi of small intestine.

A
  • goblet cells produce mucus
  • epithelial cells is where absorption takes place
  • capillary network & lacteal carry absorbed nutrients away from intestine
  • microvilli (hair-like folds on surface of epithelial cells) on the villi further increase SA
  • it is the mucosa layer of small intestine that contains villi
40
Q

How are cholesterol / fats absorbed?

A
  • absorbed into lacteal of villi
  • carried in lipoprotein complexes in the blood
41
Q

Outline digestion of starch.

A
  • amylase breaks 1,4 bonds in amylose to produce MALTOSE
  • it cannot BREAK the 1,6 bonds in amylopectin
  • these segments form dextrins
  • maltase & dextrinase break down maltose + dextrins into glucose
  • membranes in microvilli contain protein pumps that cause absorption of glucose
  • blood carrying glucose + products of digestion flows through villus capillaries to venules in submucosa of wall of small intestine
  • this then passes along the hepatic portal vein into liver where it is stored as GLYCOGEN
42
Q

Function of liver.

A
  • stores glycogen + secretes bile into small intestine
  • bile creates favorable pH for enzymes
  • bile salts emulsify fats
43
Q

Function of gall bladder

A
  • STORES bile, while liver secretes bile
44
Q

Is the small intestine alkaline or acidic?

A

ALKALINE

45
Q

example of simple diffusion

A

fatty acids

46
Q

example of facilitated diffusion

A

fructose

47
Q

example of co-transporter proteins (Active transport)

A

glucose

48
Q

examples of active transport

A

ions, amino acids

49
Q

example of endocytosis

A

cholesterol in lipoprotein complexes

50
Q

Characteristic of substance that can undergo simple diffusion.

A
  • HYDROPHOBIC
  • NON-POLAR
51
Q

Function of vagus nerve.

A

slows down heart rate

52
Q

Function of sympathetic nerve.

A

accelerates heart rate

53
Q

Outline how the heart rate is controlled.

A
  • SA node in right atrium acts as pacemaker
  • recieves electrical signals from medulla to increase / decrease rate of contraction
  • from medulla to SA node signal passes through nerves
  • sends signal down both atria, down septum to the ventricles, causing both to contract at faster rate
  • epinephrine is hormone produced by adrenal gland –> increases heart rate during fight or flight
54
Q

What is systemic circulation?

A

Pumping of blood around the body

55
Q

What is the SA node?

A

group of specialised muscle tissue

56
Q

List some components of blood

A
  • plasma / water
  • dissolved gases
  • red blood cells (erythrocytes)
  • white blood cells (leuokocytes)
  • lymphocytes + phagocytes
  • platelets
  • hormones
  • amino acids
  • antibodies
  • salts, minerals, ions
57
Q

Describe structure of arteries.

A
  • pressure is high
  • thick, muscular walls w/ collagen / elastic fibres to withstand pressure
  • elastic fibres recoil in response to ventricular contraction
  • muscle / elastic fibres help maintain pressure b/w heart beats
  • propel blood towards capillary beds (AWAY FROM HEART)
  • thick, small lumen for high pressure
  • no valves
  • smooth endothelium for efficient transport / reduced friction
58
Q

Describe structure of capillaries.

A
  • 1 cell thick (Epithelium)
  • allow for short diffusion distance for exchange of oxygen (gas exchange)
  • nutrients move into tissues
  • hormones leave capillaries in target tissues & attach to receptors on cell
  • capillaries have pores to allow lymphocytes to exit & increase permeability
  • extensive branching of capillaries increases SA
  • small diameter allows them to fit in b/w cells
59
Q

Describe structure of veins.

A
  • low pressure in veins
  • large lumen of veins –> less resistance to blood flow
  • elastic muscles
  • valves to prevent backflow
  • carry blood TOWARDS heart
  • thin walls allow skeletal muscles to exert pressure on veins
  • thin outer layer of elastic muscle provides structural support
59
Q

Describe structure of veins.

A
  • low pressure in veins
  • large lumen of veins –> less resistance to blood flow
  • elastic muscles
  • valves to prevent backflow
  • carry blood TOWARDS heart
  • thin walls allow skeletal muscles to exert pressure on veins
  • thin outer layer of elastic muscle provides structural support
60
Q

Examples of non-specific immunity

A
  • mucous membranes
  • skin –> sebaceous glands secrete lactic acid
  • inflammatory response –> swelling + heat
  • blood vessel dilation –> increase in capillary permeability
  • low pH of skin / stomach
  • cilia in trachea push out pathogens in mucous
  • phagocytosis
61
Q

Which one is soluble - fibrin or fibrinogen?

A
  • fibrinogen is SOLUBLE
  • fibrin is INSOLUBLE
62
Q

List some named proteins.

A
  • clotting factors
  • fibrin
  • thrombin (protease)
  • antibodies
  • plasma cells
  • memory cells
  • immunoglobulins
  • enzymes in phagocytic white blood cells
63
Q

Outline the functions of antibiotics.

A
  • inhibit growth of micoorganisms
  • bacteria/prokaryotic processes blocked but not processes in eukaryotes
  • block metabolic pathways (translation, cell wall formation, DNA replication)
  • DO NOT PROTECT AGAINST viruses
  • antibiotics fail to protect against bacteria if they have resistance
  • do not affect eukaryotic cells
64
Q

Why don’t antibiotics protect against viruses?

A
  1. they have no metabolism
  2. they are non-living
65
Q

Define ventilation.

A

the exchange of gases b/w lungs & air

66
Q

inspiration

A
  • external intercostal muscles contract
  • diaphragm contracts (becomes flatter)
  • ribcage moves UP & OUT
  • vol of lungs ICNREASEs, PRESSURE DECREASE
67
Q

expiration

A
  • external intercostal muscles relax
  • internal intercostal muscles contract
  • diaphragm relaxes
  • ribcage moves DOWN & IN
  • vol of lungs DECREASES, PRESSURE increases
68
Q

Distinguish b/w ventilation, gas exchange, aerobic cell respiration.

A
  • ventilation is moving air into and out of lungs/inhalation and exhalation;
  • involves (respiratory) muscle activity;
  • gas exchange involves movement of carbon dioxide and oxygen;
  • between alveoli and blood (in capillaries)
  • cell respiration is the release of energy from organic molecules/glucose;
  • (aerobic) cell respiration occurs in mitochondria;
69
Q

Example of antagonistic muscles

A

diaphragm & abdominal muscles

70
Q

What is myelin sheath composed of?

A

cholesterol / fatty acids that allows for saltatory conduction

71
Q

Define nerve impulses

A

action potentials propagated along axons of neurons

72
Q

Define local currents

A

movement of sodium ions along axon, causing depolarisation followed by repolarisation

73
Q

Why is myelination important?

A
  • it increases propagation speed
  • allows for saltatory conduction
  • permits jumping from node to node
  • myelin around neuron insulates axon
74
Q

Define synapse

A

junction b/w neurons OR b/w neurons & receptor / effector cells

75
Q

Define resting potential

A

the electrical potential difference across the plasma membrane when the cell is in a non-excited state

76
Q

What types of antigens AND antibodies are found in people with blood type B?

A
  • B antigens on their red blood cells
  • A antibodies in plasma

IB Bio (10 decks)

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