structure and function in living organisms Flashcards
1
Q
levels of organisation
A
organelles
cell: basic unit of life
tissue: Tissues are groups of cells that have a similar structure and act together to perform a specific function.
organ: a group of tissues in a living organism that have been adapted to perform a specific function
organ system: groups of organs that work together to perform a specific function
2
Q
nucleus
A
contains genetic material in chromosomes whcih controls how cells grow and work
3
Q
cytoplasm
A
supports cell structure
site of many chemical reactions
contains water and many solutes
4
Q
cell membrane
A
holds the cell together
controls substances entering and leaving the cell
5
Q
cell wall
A
gives cell extra support and defines its shape
6
Q
chloroplasts
A
site of photosynthesis
chlorophyll pigments absorb light which is necessary for the plant to grow
7
Q
vacuole
A
contains cell sap
used for storage for certain materials
also helps support the shape of cell
8
Q
mitochondria
A
site of aerobic respiration
9
Q
ribosomes
A
site of protein synthesis
10
Q
organelles in animal cells
A
The nucleus
Cell membranes
Mitochondria
Ribosomes
Cytoplasm
11
Q
organelles in plant
A
same than animal plus
cell wall made out of cellulose
chloroplasts for photosynthesis
permanent vacuole
12
Q
elements in carbohydrates and lipids
A
carbon, hydrogen and oxygen
13
Q
elements in protein
A
carbon, hydrogen, oxygen and nitrogen sometimes sulphur
14
Q
monosacharide
A
a simple sugar eg sugar or fructose
15
Q
disacharide
A
made out of two monosacharides
ex maltose formed by two glucose
or sucrose made of one glucose and one sucrose
16
Q
polysacharides
A
formed when lots of monosaccharides join together
ex starch, glycogen and cellulose
17
Q
what are proteins made of
A
amino acids
18
Q
what are lipids made of
A
fatty acids and glycerol
19
Q
test for starch
A
iodine turns form orange to black
20
Q
test for protein
A
biuret turns blue to purple
21
Q
test for sugars ex glucose
A
benedicts, sample to test tube add solutionwater bath for 5 mins
22
Q
test for lipids
A
ethano, emulsion, sample into test tube add water and shake, will turn cloudy
23
Q
enzymes
A
proteins that act as a biological catalyst
24
Q
mechanism of enzyme action
A
Step One: Enzymes and substrates randomly move about in solution
Step Two: When an enzyme and its complementary substrate randomly collide an enzyme-substrate complex forms, and the reaction occurs
Step Three: A product (or products) forms from the substrate(s) which are then released from the active site. The enzyme is unchanged and will go on to catalyse further reactions
25
how does temperature affect enzyme activity?
if enzyme work at their ptimum temperature they will work faster.
on the other hand if temperture is above optimum the enzyme will denature
26
what is an enzymes optimum ph
normally 7
ones in stomach as produced in acidic condition is ph2
ones formed in alkali conditions such as the duodenum 8 or 9
27
what happens if the ph is too far from the optimum
it will denature
28
diffusion
Diffusion is the movement of molecules from a region of its higher concentration to a region of its lower concentration
29
active transport
The movement of particles through a cell membrane from a region of lower concentration to a region of higher concentration using energy from respiration
30
osmosis
the movement of water from a area of high concentration to an area of low concentration of water through a semi permeable membrane.
31
how does surface area to volume ratio affect the rate of diffusion?
The larger the surface area to volume ratio, the quicker the rate of diffusion takes place.
32
photosynthesis formula
water + carbon dioxide = glucose + oxygen
33
limiting factors of photosynthesis
do not have unlimited supplies of their raw materials so their rate of photosynthesis is limited by whatever factor is the lowest at that time
ex light, carbon dioxide concentration and light intensity
34
how is a leaf adapted for photosynthesis
it has a large surface area to absorb more light and the diffusion of carbon dioxide
is also thin to make diffusion faster
35
key nutrients in a balanced diet
carbohydrates
vitamins
minerals (mineral ions)
dietary fibres
proteins
lipids
water
36
consequences of malnutrition
constipation-due to lack of fibre
starvation
coronary heart disease- diet to high in saturated fats and cholesterol
obesity
37
sources and functions of dietary elements
carbohydrates- source of energy, found in pasta, cereal, rice and potatoes
protein- growth and repair , found in meat, eggs, fish and nuts
lipids- insulation and energy storage, found in butter, oil and nuts
dietary fibre- peristalisis, found in vegetables and whole grains
vitamins- needed in small quantities to mantain health, found in fruits and vegetables
minerals- needed in small quantities to mantain health, found in fruits, vegetables, meat and vegetables
38
enzymes in mouth
amylase
39
enzymes in stomach
protease
40
enzymes in pancreas
all three types of enzymes
41
peristalisis
Peristalisis is a mechanism that helps moves food along the alimentary canal
42
what type of muscles control peristalisis
Peristalsis is controlled by circular and longitudinal muscles
Circular muscles contract to reduce the diameter of the lumen of the oesophagus or small intestine
Longitudinal muscles contract to reduce the length of that section the oesophagus or the small intestine
43
what is the purpose of digestion
to break down large, insoluble molecules into smaller, soluble molecules that can be absorbed into the bloodstream
44
amylase function
breaks down starch into maltose
45
maltase function
breaks down maltose into glucose
46
protease function
breaks down protein into amino acids
47
lipase function
breaks down lipids into fatty acids and glycerol
48
where is bile created and stored?
bile is created in the liver
before entering the small intestine is stored in the gallbladder
49
function of bile
neutralizes the ph of the stomach/ hydrochloric acid
emulsifies lipids
50
how are villi adapted to its function
a large surface area- Microvilli on the surface of the villus further increase the surface available for absorption
a short diffusion distance- wall of villus only one cell thick
a steep concentration gradient
51
aerobic respiration formula
glucose + oxygen = carbon dioxide + water
52
what is the unit of energy
ATP ( adenosine triphosphate )
53
anaerobic respiration in animals formula
glucose = lactic acid
C6H12O6 = 2C3H6O3
54
what is the oxygen debt
the amount of oxygen required to break down the lactic acid
55
what does lactic acid do to our body
builds up in muscle and lowers the ph in muscle tissue, which could denature enzymes.
56
function of external intercoastal muscles
pull ribcage up
57
function of internal intercoastal muscles
pull ribcage down
58
what happens to respiratory system during inhalation
The diaphragm contracts and flattens
The external set of intercostal muscles contract to pull the ribs up and out:
This increases the volume of the chest cavity (thorax)
Leading to a decrease in air pressure inside the lungs relative to outside the body
Air is drawn in
59
what happens to respiratory system during exhalation
The diaphragm relaxes it moves upwards back into its domed shape
The external set of intercostal muscles relax so the ribs drop down and in
This decreases the volume of the chest cavity (thorax)
Leading to an increase in air pressure inside the lungs relative to outside the body
Air is forced out
60
what is tar
a carcinogen (a substance that causes cancer)
61
what is nicotine
an addictive substance which also narrows blood vessels
62
what is carbon monoxide
reduces the oxygen-carrying capacity of the blood as it binds with haemoglobin
63
accross which organelle does gas exchange occur
cell membrane
64
what are the three transport processes in living organism used for exchange
diffusion, active transport and osmosis
65
why do unicellular organisms dont need the main transpor system
Unicellular organisms do not require transport systems due to their large surface area to volume ratio
66
what does blood cells consist off
mainly plasma and red blood cells they also contain white blood
67
blood cells
concave discs containig no nucleus but plenty of haemoglobin
68
platelets
fragments of cells
69
plasma function
plasma is important to carry substances like:
urea
carbon dioxide
digested food and mineral ions
hormones
heat energy
70
adaptations of red blood cells
full of haemoglobin
no nucleus- more space for haemoglobin
biconcave shape- more surface area to volume ratio
71
phagocytosis
process of engulfing and digesting bacteria
72
what is the function of a lymphosite
produce antibodies
73
what are antibodies
Antibodies are Y-shaped proteins with a shape that is specific (complementary) to the antigens on the surface of the pathogen
74
what does antibodies do when attached to antigen
Antibodies attach to the antigens and cause agglutination (clumping together)
This means the pathogenic cells cannot move very easily
At the same time, chemicals are released that signal to phagocytes that there are cells present that need to be destroyed
75
what does lymphosites produce to neutralize toxins made by pathogens
antitoxins
76
what group of cells controlls the heart rate
pacemakers
77
pacemakers function
coordinate the contraction of the heart muscle and regulate the heart rate
Pacemaker cells send out electrical impulses which initiate a contraction in the cardiac muscle
78
what does your body require when increasing heart rate?
An increase in respiration means an increase in requirement for oxygen and glucose as well as an increase in production of waste products that need to be removed
79
what happens to the heart rate and blood flow when there is an increase in heart rate?
Heart rate increases to deliver oxygen and glucose and remove waste more frequently
The volume of blood pumped out of the heart also increases to deliver bigger quantities of oxygen and glucose
80
what hormone increases heart rate?
adrenaline increases heart rate as a fight or flight response
81
what is coronary heart disease
consists of layers of fatty material mainly made of cholesterole building up inside coronary arteries
82
risk factors of coronary heart disease
obesity
high blood pressure
high cholesterole
smoking
83
features of arteries
Carry blood at high pressure away from the heart
Carry oxygenated blood (except the pulmonary artery)
Have thick muscular walls containing elastic fibres
Have a narrow lumen
Blood flows through at a fast speed
84
how is an artery adapted to its function
Thick muscular walls containing elastic fibres withstand the high pressure of blood and maintain the blood pressure as it recoils after the blood has passed through
A narrow lumen also helps to maintain high pressure
Veins
85
features of veins
Carry blood at low pressure towards the heart
Carry deoxygenated blood (other than the pulmonary vein)
Have thin walls
Have a large lumen
Contain valves
Blood flows through at a slow speed
86
how is a vein adapted to its function
A large lumen reduces resistance to blood flow under low pressure
Valves prevent the backflow of blood as it is under low pressure
87
features of capillaries
Carry blood at low pressure within tissues
Carry both oxygenated and deoxygenated blood
Have walls that are one cell thick
Have ‘leaky’ walls
Speed of blood flow is slow
88
adaptations of capillaries
Capillaries have walls that are one cell thick (short diffusion distance) so substances can easily diffuse in and out of them
The ‘leaky’ walls allow blood plasma to leak out and form tissue fluid surrounding cells
89
what are venules and arterioles
narrow vessels that connect capillaries to arteries and veins, arteries and veins get narrower as they get away the heart.
90
examples of waste products in a plant
Oxygen
Carbon dioxide
Water/water vapour
Other unwanted chemical substances
91
4 extretary organs
The kidneys for the excretion of urea, water and mineral ions
The lungs for the excretion of carbon dioxide and water
The skin for the excretion of excess mineral ions (e.g. sodium) and water
The liver for the breakdown of proteins (amino acids) into urea
92
dangers of waste products
Toxicity - waste products can have toxic effects if they are allowed to reach high concentrations
Carbon dioxide dissolves in water easily to form an acidic solution which can lower the pH of cells. This can reduce the activity of enzymes in the body which are essential for controlling the rate of metabolic reactions
Osmotic effect - body fluids can become more concentrated due to higher amounts of waste products
93
homoestasis
Homeostasis is critically important for organisms as it ensures the maintenance of optimal conditions for enzyme action and cell function
94
what are the two communication systems that do homoestasis
The nervous system
The endocrine system
95
cooling mechanisms
vasodilation- widening of blood pressure
sweating-This cools the skin by evaporation which uses heat energy from the body to convert liquid water into water vapour
flattening of hair cells-The hair erector muscles in the skin relax, causing hairs to lie flat
This stops them from forming an insulating layer by trapping air and allows air to circulate over skin and heat to leave by radiation
96
all controll systems that carry out a coordinated response need
A stimulus (a change in the environment e.g. a change in glucose levels in the blood, a change in body temperature etc.)
A receptor (receptor cells that detect stimuli)
A coordination centre (such as the brain, spinal cord and pancreas), which receives and processes information from receptors
An effector (a muscle or gland), which brings about responses to restore optimum levels
97
what is a tropism
The directional growth responses made by plants in response to light and gravity
98
positive tropism
If the growth is towards the stimulus
99
negative tropism
if the growth is away from the stimulus
100
geotrophic response
respone to gravity
101
phototropic
response to light intensity
102
auxins
growth regulators in plants which coordinate and control directional growth responses.
ex phototrophisms and geotrophisms
103
where are auxins created
Auxins are produced in the tips of the shoots and the roots
104
what effects does auxins have on the shoots?
auxins promote cell elongation (growth); more auxin = more cell elongation = more growth
105
what effects does auxins have on roots?
auxins limit cell elongation (growth); more auxin = less cell elongation = less growth
106
how is the distribution of auxin affected by in roots and shoots?
in roots is affected only by gravity
in shoots is affected by gravity and light
107
what composes the central nervous system
brain and spinal chord
108
what composes the periferal nervous system
nerves
109
types of neurons
Sensory neurones carry impulses from sense organs to the CNS (brain or spinal cord)
Relay neurones are found inside the CNS and connect sensory and motor neurones
Motor neurones carry impulses from the CNS to effectors (muscles or glands)
110
pathway through the nervous system
stimulus → sensory neurone → relay neurone → motor neurone → effector → response
111
synapse function
to transmit the impulse from one nurone to another neurone
112
neurotransmitters
chemicals created and stored in vesicles in the presynaptic membrane
113
what happens when neurotransmitters are triggerd
they diffuse across the synaptic cleft
they bind to to receptors in the postsynaptic membrane and trigger a nerve impulse
114
what does the term synapses are undirectional
means that they only transmit imoulses in one direction
115
reflex arc
The pin (the stimulus) is detected by a (pain/pressure/touch) receptor in the skin on the person's foot
A sensory neurone sends electrical impulses to the spinal cord (the coordinator)
An electrical impulse is passed to a relay neurone in the spinal cord (part of the CNS)
A relay neurone synapses with a motor neurone
A motor neurone carries an impulse to a muscle in the leg (the effector)
When stimulated by the motor neurone, the muscle will contract and pull the foot up and away from the sharp object (the response)
This all occurs within a fraction of a second
