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IGCSE umaima > biology > Flashcards

biology Flashcards

1
Q

Hepatic portal vein

A

Carries digested food from the small intestine to the liver.

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2
Q

Hepatic vein

A

Carries deoxygenated blood back to the heart. Carries digested food (glucose and amino acids) from the liver around the body.

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3
Q

Renal artery

A

Carries oxygenated blood (also rich in urea) to the kidneys for excretion.

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4
Q

Renal vein

A

Carries deoxygenated blood (also low in urea as it has been purified in the kidney) back to the heart.

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5
Q

where are the cornorary arteries located

A

they branch off from the aorta and supply the heart muscle with glucose and oxygen for respiration on the external surface.

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6
Q

limiting factors in graphs for photosynthesis

A

when the gradient is increasing the limiting factor is the x axis itself, however when it is constant the l.f is either : light intensity, CO2 conc or temperature

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7
Q

function of ribs

A

bone structure that protects internal organs such a the lungs

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8
Q

function of the intercoastal muscles

A

muscles between the ribs which control their movement causing exhalation and inhalation, by pulling the rib cage up or down

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9
Q

function of trachea

A

Rings of cartilage surround the trachea (and bronchi)
The function of the cartilage is to support the airways and keep them open during breathing
If they were not present then the sides could collapse inwards when the air pressure inside the tubes drops

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10
Q

function of mucus and cilia

A

The mucus is produced by goblet cells and traps bacteria, dust, particles
The cilia beat
And push the mucus away from the lungs towards the throat

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11
Q

where else does mechanical digestion take place other than the mouth

A

stomach, churning snd turning food. contracting muscular action of stomach

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12
Q

species

A

a group of organisms that can

reproduce to produce fertile offspring

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13
Q

define transpiration

A

loss of water vapour
from plant leaves by evaporation of water at
the surfaces of the mesophyll cells followed by
diffusion of water vapour through the stomata

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14
Q

define translocation

A

the movement of
sucrose and amino acids in phloem:
– from regions of production (source)
– to regions of storage OR to regions where
they are used in respiration or growth (sink)

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15
Q

define synapse

A

a junction between two

neurones

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16
Q

define population

A

a group of organisms of one

species, living in the same area, at the same time

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17
Q

dine community

A

all of the populations of

different species in an ecosystem

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18
Q

define ecosystem

A

a unit containing the
community of organisms and their environment,
interacting together e.g a lake or decomposing log

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19
Q

define sexual reproduction

A

a process involving
the fusion of the nuclei of two gametes (sex cells)
to form a zygote and the production of offspring
that are genetically different from each other

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20
Q

define fertilzation

A

fusion of gamete nuclei

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21
Q

recessive

A

an allele that is only expressed
when there is no dominant allele of the gene
present

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22
Q

functions of fats

A
  • source of energy
  • prevents water from being lost from the skin
  • makes up cell membrane
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23
Q

function of bile

A

neutralizes the acidic stomach chyme, pprovides alkaline conditions,

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24
Q

codominance

A

both alleles are expressed to an extent. eye color, blood type

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25
Q

continuous variation

A

bpdy mass, skin color, s.a of leaves, height. genes can be affected by the enviornment. has intermediates. line graohs

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26
Q

discontinuos variation

A

blood group, gender , albino. ability to roll tounge. distinct categories. bar graphs

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27
Q

what is gene mutation

A

change in meosis, then sequence of dna leading to change in genotype of the offspring

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28
Q

explain why conserving animals is important

A
  • maintains food chains - encourages biodiversity
  • source of research - prevents extinction
  • food for predators
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29
Q

disavantages of asex

A
  • no variation - bad traits easily passed
  • one disease can wipe out whole population
  • more competition - less chance of adapting in varying enviornment
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30
Q

disadvantages of sex reprod.

A
  • slow - takes two parents - less energy efficient

- offspring may not be well adapted to the env.

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31
Q

advatages of meosis to a species

A
  • genetic variation
  • evolution occurs
  • natural selection thru ompetition for survival
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32
Q

describe the process of inhalation

A
  • diaphram contracts and flattens
  • ribcage is lifted upwards
  • external contract internal relax
  • volume of chest increases
  • pressure inside of lungs decreases thus air flows down a pressure gradient
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33
Q

name the part of the blood where minerals, ions, molecules, and gases are transported

A

plasma

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34
Q

why does the rate of CO2 diffusion increase during exercise?

A
  • more aerobic respiration

- steeper concentration gradient

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35
Q

outline how water that has entered a root hair cell reaches the stomata

A

osmosis. through partially permeable membrane from roots into xylem, water molecules stick together as cohesion occurs which creates tension in the water column and water moves up into the leaf through osmosis. evaporation of water vapors from surfaces of mesophyll layer into air spaces

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36
Q

spongy mesophyll is a

A

tissue

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37
Q

characteristics of wind polinated plant

A 
feathery stamen
light pollen 
large anthers
no petals 
anthers and stamen hanging outside
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38
Q

explain the role of enzymes in seed germination

A
  • enzymes are required in the process of respiration

- the stored food reserves in the seed are broken down

39
Q

how to recycle paper

A
  • shredding, pulping, deinking bleaching, rolled out and pressed
40
Q

how is villi adapted for its finctions

A
  • elongated structure
  • richly supplied with blood capillaries which allow constant blood flow rich with glucose, amino acids, minerals)
  • lacteal absorbs fatty acids
  • 1 cell thick lining makes absorption faster
  • microvilli increases surface area
  • goblet cells produce mucus which lubricates and protects the intestine from digestive juices
41
Q

describe movement of peristalsis

A

behind the food - circular contracts longitudinal relax which pushes food forward. in front its vice versa to allow food to pass the alimentary canal.

42
Q

why do plants need nitrates

A

to make proteins and for growth. without protien the amt of chlorophyll in leaves decreases so does rate of photosynthesis so the leaves turns pale yellow. thus nitrates are a limiting factor.

43
Q

steps of sewage treatment

A
  1. screened/filtered to remove solids
  2. sedimentation tanks. sludge is decomposed by anaerobic bacteria
  3. in aerobic conditions bacteria decompose the effluent by breaking down complez compounds into smaller soluble ones with enzymes.
  4. bacteria is killed by treating the water with chlorine
44
Q

pollution in water by non biodegarable materials

A
  • bioaccumalation
  • toxic materials enter food chains
  • cant be digested / decomposed
  • injures animals
  • blocks sunlight so hinders photosynthesis
  • blocks flow of water so less aeration , decreases conc of dissolved oxygen
45
Q

explain how strains of antibiotic resistant bacteria is formed and then spread?

A
  • mutation occurs in gene which results in change of dna so new alleles could be expressed - produces different protein
  • as a result of natural selection, they reproduce and multiply whereas when antibiotics are taken the vulnerable bacteria are affected so theres less competition
  • can spread through unprotected sexual intercoarse
46
Q

why is food stored in the form of starch and glycogen?

A
  • large and insoluble so in diffusible
  • cant be lost from cell
  • insoluble so they dont disturb the water potential
  • compact shape they take up less space
  • easily could be hydrolyzed back into glucose
47
Q

what 3 hormones affect conc of glucose in blood?

A
  • adrenaline

- insulin - glucagon (secreted from pancreas) targets liver

48
Q

advantatges of using bacteria in genetic engineering

A
  • asexual less energy rapid
  • identical
  • no ethical issues
  • produces large amt of insulin
  • all bacteria have the gene that produces insulin
49
Q

function of fragments of cells involved in blood clotting

A

Platelets release chemicals that cause soluble fibrinogen proteins to convert into insoluble fibrin and form an insoluble mesh across the wound, trapping red blood cells and therefore forming a clot
The clot eventually dries and develops into a scab to protect the wound from bacteria entering. calcium helps promote blood clotting

50
Q

function of plasma

A

90% water
acts as a solvent for dissolved substances and minerals
- distributes heat realeased during metabolic reactions
transports hormones to target organs

51
Q

what are plasmids

A

small rings of genes in which chromosomes could be inserted for the purposes of genetic engineering

52
Q

how does transpiration occur?

A

water evaporates from surfaces of mesophyll cells into air spaces of leaf. the loss of water from the leaf lowers its water potential which creates tension in the water column in xylem and cohesion of water molecules occur

53
Q

define anaerobic respiration

A

the release of relatively small amt of energy by the breakdown of glucose with oxygen.

54
Q

describe the process of deamination

A

amino acids are proccessed in the liver. the nitrogen containing part of the amino acid is highly toxic and needs to be removed. part of the amino acid is converted into ammonia which is converted into urea

55
Q

functions of liver

A
  • bile production
  • deamination
  • storage of glycogen
56
Q

eutrophication

A

sewage runoff

  • decomposition of waste
  • bacteria respires
  • reduced dissolved oxygen content
  • death of aquatic organism
  • for fertilizer runoff
  • algal blooms due to nitrates in runoff
  • bacteria feed on them
57
Q

why is eating tertiary consumer less efficient

A
  • 10 % energy loss throughout the trophic levels
  • some parts are indigestable
  • energy lost in repiration and movement
  • lower trophic levels have the most energy
58
Q

how are arteries adapted for their function

A 
- thick wall
withstands high blood pressure
- muscular tissues
vasodilation and vasconstriction occur
- small lumen 
maintains blood pressure
- elastic tissue
can strech
59
Q

where is progesterone released

A

corpus luteum and placenta

60
Q

outline two social implications of using fertility drugs

A
  1. multiple eggs could be released at once ; so triplets or twins
  2. religious prohibition
61
Q

fetility drugs

A
  • injected or taken in the form of a pill
    early into the menstrual cycle
  • inhibits activity of oestrogen
  • FSH stimulates development of follicle , more eggs are released
  • LH stimulates ovulation ; release of eggs
62
Q

state why downstream processing is nessacairy in fermentation

A
  • purifies and separates penicillin from waste and toxins
  • maximum concentration
  • making it into pills which could be used in medicine
63
Q

discuss the long term effects of self pollination on the evolution of these plant species

A
  • most variation s only due to mutation and mutation is very rarely expressed
  • hard to adapt to change in enviornment
  • competition
  • can be wiped out by one disease
64
Q

how does adrenaline prepare the body for action

A
  • pupils dilate
  • increased glucose conc in blood
  • rate of respiration increases heart beats fatester
65
Q

how does impulse travel across synapse?

A

an impulse triggers the release of neurotransmitters which diffuse across the gap and bind to receptors which allows the passage of impulse

66
Q

nerve impulse

A

an electrical signa; which passes along a neurone in one direction

67
Q

why must antibodies be injected instead of mouth

A
  • are protiens
  • can be denatured shape change in alimentary canal
  • direct route to the site of infection
68
Q

why isnt passive immunity long term

A
  • no memory cells are produced
  • antibodies are broken down in the body
  • the antibodies are not made by th body’s own lymphocytes
69
Q

different nutrients required by plants

A
  • nitrates making proteins from amino acids for growth
    w/o it stunted growth and yelowing of leaves due to reduced chlorophyll
  • magnesium deficieny results in reduced phtocynthesis and yellowing beteen veins of leaves chlorosis and mg is needed to make chlorophyll
70
Q

describe the cause of sickle cell anaemia

A
  • mutation
    change in gene’s base sequence
    -inherited allele passed down from carrier
  • sickle shape
  • having the recessive allele being homozygous
  • abnormal hemoglobin produced Hbs
  • stick together and clot.
71
Q

other than ph and temp what else affects ezyme activity

A

. concentration

. s.a of substrate

72
Q

what causes the semi lunar valves do close during a heart beat

A

ventricles relax. increased volume of ventricles.

73
Q

how does acid rain affect freshwater ecosytems

A
  • Aluminium ions become mobile which are highly toxic
  • shells are damaged
  • frogs cant reproduce
  • fish produce mucus which blocks their gills
  • nutrients such as MG and Ca are leached
74
Q

treatments for cornorary heart disease

A
  • drug treatment ; aspirin which prevents blood from clotting
  • angioplasty a balloon is attached an inflated, to widen the artery
  • cornorary bypass a different artery is attached to carry blood around the blocked artery
  • a stent could also be placed to widen the artery.
75
Q

how does heroin affect the nervous system

A

When it enters the brain, heroin is metabolised to morphine
Morphine molecules fit into some of the endorphin receptors and this is why taking heroin makes users feel so good
Taking heroin can reduce the production of natural endorphins and other neurotransmitters, which is why repeated use leads to the need for greater and greater amounts in order to get the same feelings

76
Q

which part of the eye prevents internal reflection

A

choroid

77
Q

where is energy lost in between food chains

A

during excretion and respiration

78
Q

which feature do annelids and arthopods both share?

A

segmented bodies

note that only arthopods have jointed legs

79
Q

which cells dont have a nucleus

A

rbcs and xylem

80
Q

Ligase enzymes function in genetic engineering

A

Join human DNA to plasmid DNA

81
Q

What does the restriction enzymes do?

A

Isolates the required gene leaves it with sticky ends.

used to cut the plasmid open

82
Q

With which kingdoms do bacteria share the same genetic code?

A

Animal
Plant
Fungi
Protoctist

83
Q

Describe the development of cholera

A
  1. Toxins are produced by the bacterium
  2. Chloride ions are secreted into the gut
  3. Osmosis causes water to move into the gut
  4. The infected person is dehydrated
84
Q

Where is xylem

A

Xylem is located on the inner part of the plant. It takes more up more area in root

85
Q

Are there more cone or rod cells in the retina?

A

3 types of come cell

Whereas 1 type of rod cell

86
Q

Which process occurs during transpiration

A

Movement of water vapor through the stomata by diffusion

87
Q

Which chamber of the hart has the most muscular wall

A

Left ventricle

88
Q

What happens to circular and radial muscles when they enter a brightly lit area

A

Circular muscles : contract
Radial : relax
Pupil : constricts

89
Q

How much is the pressure in the thorax when breathing out

A

High

90
Q

What is a function of the placenta

A

Dissolved nutrients exchange

NOT transfer of blood

91
Q

When we exhale what happens to the diaphragm

A

Rises

92
Q

Why does tissue rejection occur?

A

New part has antigens on it with triggers immune response as in antibody production

93
Q

What statement about submerged leaves is correct?

A

They offer little resistance to water flow

94
Q

What organ released glucagon

A

Pancreas

IGCSE umaima (9 decks)

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