4th Form Flashcards
1
Q
Producer
A
organisms which make their own food
2
Q
Consumer
A
Organisms which eat other living things
3
Q
Decomposer
A
Organisms which secrete digestive enzymes to decay dead organic matter to obtain their food; they help to recycle nutrients
4
Q
Population
A
The total number of individuals of one species in a particular habitat at a particular time.
5
Q
Give some reasons for energy loss between trophic levels
A
Not al the organism is eaten
Not all the organism is digested
Some materials were respired (cell division)
6
Q
Decomposers to Atmosphere
A
Respiration
7
Q
Atmosphere to plants
A
Photosynthesis
8
Q
Plant to decomposer
A
Death
9
Q
Plant to atmosphere
A
Respiration
10
Q
Fossil Fuels to atmosphere
A
Burning
11
Q
Plants to animals
A
Feeding
12
Q
Define Nitrogen Fixation
A
Nitrogen-fixing bacteria in the soil and roots of legume plants absorb nitrogen and reduce it to make ammonia.
13
Q
Define nitrification
A
Ammonia converted to nitrites and nitrates by nitrifying bacteria.
14
Q
Define denitrificaiton
A
Nitrates are converted to nitrogen gas
15
Q
Define decomposition
A
Protein in dead plants and animals is broken down.
16
Q
Define ammonification
A
The process of converting natural nitrogen compounds into ammonia.
17
Q
How is the relationship between nitrogen fixing bacteria living on root nodules and the plant mutualistic?
A
the bacteria receive glucose from the plant, while the plant absorbs ammonia from the bacteria in the nodule.
18
Q
2 carbohydrates found in plants
A
Starch, cellulose
19
Q
The nitrogen in a nitrate ion in the soil can become the nitrogen in a protein molecule in an animal- explain how this happens
A
Assimilation – nitrates from the soil are absorbed by the roots and are used to make amino acids and proteins which are incorporated into the plants. Animals then eat the plants and the nitrogen in the plants is transferred to proteins in the animal.
20
Q
Animal to atmosphere
A
death
21
Q
Fossil fuels to factorys
A
Extraction
22
Q
Factorys to atmosphere
A
Combustion
23
Q
Eutrophication + consequences
A
When a large number of algae is growing on the water surface
Low oxygen level suffocates fish
More anearobic bacteria- stagnant/ smelly water
24
Q
Explain how chemical fertilisers increase crop yields
A
Nitrgon needed to produce ATP
Chemical fertilisers have nitrogen
Nitrogen is needed to make amino acids, proteins and artifical enzymes
DNA and enzymes are essential for cell reproduction
25
Biome
Large areas dominated by a specific type of vegetation
26
Define greenhouse gas
A greenhouse gas is a gas that absorbs and emits radiant energy within the thermal infrared range, causing the greenhouse effect.
27
Mitosis differences as opposed to meiosis
Produces genetically identical daughter cells
Produces two cells
Involves one division
Produces diploid cells in humans
Keeps the same chromosome number
28
Meiosis differences
Produces genetically non-identical
daughter cells
Produces four cells
Involves two cell divisions
Produces haploid cells in humans
29
Describe the steps of mitosis
1.The cell grows
2.The DNA replicates to form two copies of each chromosome. These copies are joined together at a single point (the centromere).
2. The nuclear membrane breaks down. The chromosomes line up across the centre of the cell, attached to special spindle fibres
3. The chromatids (copies of chromosomes) are pulled apart and move to opposite ends of the cell.
4. The cytoplasm and cell membrane divides to form two identical cells.
30
Describe steps for meiosis
1.
The DNA replicates to form a copie of each chromosone,
2.
The nuclear membrane breaks down. The homologous pairs of chromosomes join together.
3.
The homologous pairs of chromosomes exchange sections of DNA. They then attach to the
spindle fibres in pairs, at the centre of the cell.
4.
The homologous pairs of chromosomes are pulled apart and move to opposite ends of the cell. The cell divides.
5.
The chromosomes line up along the centre of the cell, attached to the spindle fibres. The
chromatids separate and move to opposite ends of the cell. Each cell divides again.
31
Ovary
Where egg cells are formed by meiosis (in the follicle). Produces the hormones oestrogen and progesterone.
32
Oviduct
Egg cells travel down this to the uterus. Lined with cilia which move the cell. Site of fertilisation
33
Uterus
A lining forms in the uterus, where the embryo will implant.
The foetus develops in the uterus, which has a thick muscular wall. This contracts during labour.
34
Cervix
Narrow opening to the uterus. This dilates (widens) during labour, to allow the baby to be born.
35
Testes
where sperm cells are formed by meiosis. Produces the hormone testosterone.
36
Prostate Gland
Release liquids into the sperm duct, which mixes
with the sperm cells to form semen. The liquid provides nutrients to the sperm.
37
Male reproductive system
38
Female reproductive system
39
role of amniotic fluid
protection from mechanical shocks, tempurature chanches
40
Role of placenta
Nutrient movement
Transportation of metabolic wastes
(all via diffusion)
41
Why do the circulatory systems of the mother and foetus not mix?
1. Mothers white blood cells might attack the babys blood
2. Mother has higher blood pressure
42
Boys puberty changes
Deeper voice
Broader shoulders
Pubic hair
43
Girls puberty changes
Pubic hair
menstrual cycle begins
Deeper voice
44
FSH- gland , effect, stage released
Pituitary gland,
eggs matures and follice develops,
released start of ovulation/ stage 3
45
Oestrogen- gland, effect, stage released
Ovary, inhibits FSH production, released start of ovulation ( stage 3)
46
LH- gland, effect, stage released
pituitary gland, follicle releases ovum into oviduct+follicle turns into corpus luteum, released start of stage 3 (ovulation)
47
What hormone does the follicle produce? What Hormone does the corpus luteum produce?
Follicle- Oestrogen. Corpus Luteum- Progesterone
48
Progesterone -gland, effect, stage released
Ovary, FSH and LH inhibited+ uterus lining maintained, after ovulation/ stage 4
49
3 methods of asexual reproduction in plants
Tubers
Runners
Bulbs
Cuttings (artifical)
50
Where is pollen produced?
Anther
51
What is the anther?
The part of the stamen where pollen is produced.
52
Where are ova produced?
Ovules
53
What is the carpel?
The part of the flower where the Ovules are
54
Insect vs wind pollinated flowers
Stamen- enclosed within flower vs Stamen- Exposed outside of petals
Stigma-enclosed within flower and sticky vs exposed outside of petals, often ‘feathery’
Petals Large and brightly coloured vs small, usually green
Nectaries Present - produce sugary fluid to attract insects
vs Absent
55
Plant diagram.
56
Stages of plant fertilisation
1. In plants pollen grains are deposited onto the stigma.
2. The pollen grain goes down a pollen tube which goes down through the style.
3. Enzymes are secreted at the tip of the tube which digest the tissues of the style.
4. When the tube reaches an ovule the male gamete travels through the tube entering the ovule through a small hole called the micropyle.
5. It then fuses with the female gamete (ovum) in the process of fertilisation.
6. The fertilised ovum divides by mitosis to form the embryo
7. The ovule develops into the seed.
8. The ovary develops into the fruit
57
Diffusion definition
Diffusion is the random movement of particles from an area of higher concentration to an area of lower concentration.
58
Osmosis Definition
Osmosis is the net diffusion of free water molecules from an
area of high water concentration to an area of low water concentration across a partially permeable membrane
59
Osmosis Diagram in plant and animal cells
60
Active transport definition
Active Transport is the movement of molecules from an area of low concentration to an area of high concentration using ATP
61
What does the xylem transport and why are the transported substances essential for a plant?
Transports water and mineral
ions from the roots to the leaves.
Nitrate ions are needed to make
amino acids and proteins
Magnesium ions are needed to
make chlorophyll
62
What makes the xylem cell was waterproof
Cell wall contains lignin -
waterproof
63
Describe the structure of the xylem
Made up of thick walled dead
cells which contain no cytoplasm -
they are completely hollow and
arranged end to end
End wall are broken down
64
Describe the structure of the phloem
Consists of living cells.
Tubes are formed by cells
arranged end to end but have
cell walls made of cellulose.
65
What does the ploem transport and why are the transported substances essential?
Sucrose, Amino acids. Essential for respiration.
66
Where does the ploem transport it's materials?
Phloem transports sucrose and
amino acids from the leaves
(where they are made) to the
growing points (eg the tips of
the shoot and flowers) or
storage areas (such as the roots
or bulbs).
67
What is transpiration ?
Transpiration is the evaporation of water from the surface of a plant
68
Give 4 factors that affect transpiration
Tempurature
Wind speed
Humidity
Light
69
How are root hair cells adapted for diffusion?
Thin walled for shorter diffusion distance
Hair like extension for greater SA
70
Functions of transpiration
To carry mineral ions to the leaves for the synthesis of amino acid and chlorophyll.
To keep turgor pressure high in leaf cells, holding the leaves up.
Evaporation cools the leaves.
Supplies water for photosynthesis
71
Name of the movement of contents in plants up or down
Translocation
72
What happens to the stomata in light and dark
Light- the Guard cells open and the stomata beomce turgid
Dark- THe guard cells close and become flacid
73
Why do the stomata open in Light?
In the light the guard cells photosynthesise. The concentration of sugars increases, the water potential in the guard cells falls and so water moves into the guard cells by osmosis.
They become turgid (swollen) - this causes the guard cells to become banana shaped, due to the inflexible inner cell wall, and opens the stomata.
74
What flows through the sieve tube?
A concentrated solution of amino acids and sucrose
75
Carbon dioxide- where is it formed, how is it made, and where is it excreted
Formed in respiring cells, made via respiration, excreted via the lungs
76
Urea- where is it made, how it it made, and where is it excreted
Liver cells, deamination, excreted through kidneys and skin.
77
Where are amino acids filtered in?
hepatic artery and hepatic portal vein.
78
Describe the areas of the kidney
Around the outside and a lighter colour is the
cortex. In the middle are the triangular
shaped medulla and finally in the centre is
the pelvis.
79
What are the role of the nephrons
To filter blood
80
Describe the process of Ultrafiltration
1. Blood is pumped at very high pressure. This pressure forces small molecules such as urea, glucose, amino acids and salts out of the capillaries of the glomerulus and into the Bowman’s Capsule. This forms the glomerular filtrate. 2. Larger molecules like proteins or red blood cells are too big to fit across the capillary walls
and therefore stay in the blood.
81
Describe selective reabsorbtion
The filtrate in the Bowmans capsule travels to the proximal convoluted tubule (PCT). However it contains a lot of useful materials such as glucose which would be wasted unless they were recovered. There are specialised cells within the walls of the Proximal Convoluted Tubule. These move the useful materials back into the blood stream. Initially molecules will move by diffusion, but some substances are also moved against a concentration gradient using ATP. This is called active transport
82
Describe Water reabsorbtion in the loop of Henle
Ascending tube absorbs Na and Cl- creates a salty environment. Decensing tube lets water osmose into the Saline solution.
83
What do the osmoreceptors do?
Release ADH ( turns collecting tube permeable to allow for more water absorbtion when dehydrated)
84
Why is urine more dilute when people are hydrated?
The osmoreceptors stop releasing ADH and so all the water is moved into the Urea.
85
How is the leaf specialised for gas exchange?
The leaf is thin, so the diffusion distance is short
It has a large surface area, increasing no. of stomata so gases can diffuse quicker
The guard cells form the stomata and can change shape, altering the size of the stomata
The stomata close to reduce water loss
86
Where is Co2 made, how is it made, and where is it removed?
Made in respiring cells, via respiration, removed via lungs
87
Where is Urea made, how is it made, and where is it removed?
Made in Liver cells, made via the breakdown of amino acids, and removed through the kidneys and skin.
88
Functions of transpiration stream
To carry mineral ions to the leaves
To keep turgor pressure high
Evaporation cools the leaves
Supplies water for photosynthesis
89
What could be used to demonstrate a partially permeable membrane in investigating factors of osmosis and and diffusion
Visking Tubing
90
What is a stimulus
Change in surroundings
91
Receptor
The organ that detects the change
92
Effector
Muscles that respond to the stimulus
93
Central nervous system
Consists to the brain and spinal cord. Co-ordinates nervous reflexes like moving+reflexes
94
Peripheral Nervous system
Contains the nerves that send impulses to the effectors
95
Name the 3 types of Neurones
Sensory, relay, motor
96
timeline of stimulus to effector
receptors detect a stimulus,
stimulus to receptor
receptors to sensory neuron
sensory neuron to brain
brain to relay neuron
relay neuron to motor neuron
motor neuron to effector
97
Nucleus
Contains genetic material
98
Dendrite
Connections that link to other neurons
99
Axon
The section electrical impulses travel across
100
Myelin sheath
Insulates Axon and speeds up electrical impulses
101
Name the 2 muscles in the Iris and what they do in different light conditions
Radial (contract in dim and relax in bright) Circular (contract in bright and relax in dim)
102
Describe the process that occurs in the eye when looking at an object far away
1. Relaxes ciliary muscles
2. So the suspension ligament is pulled tight
3. So the lenses are stretched thin
4. So there is less light refraction (light rays are parallel so no need for high refraction)
103
Describe the process that occurs in the eye when looking at an object close up
1. contracts ciliary muscles
2. So the suspension ligament is slacker
3. So the lenses are thicker
4. So there is more light refraction (light rays come at a wide angle so high refraction needed)
104
Endocrine system vs Nervous system speed of action
Endoctrine is slow, nervous is fast
105
Endocrine system vs Nervous system type of message
Endoctrine is chemical while nervous is via electrical impulse
106
Endocrine system vs Nervous system transport method
Endocrine system is via the plasma in blood the nervous system is along neurones
107
Endocrine system vs Nervous system response to signal
Endocrine is sends to the whole body but only target cells respond and Nervous is directly sent to a muscle or gland
108
Endocrine system vs Nervous system role
Endocrine controls long term processes like growth nervous is for a fast response
109
Name the 6 major glands in the human body
Thyroid gland
Brain
Pancreas
Testis
Ovary
Adrenal glands
110
Insulin- gland and function
Pancreas- manages blood sugar levels by conversions of glucose into glycogen
111
ADH- gland and function
Pituitary gland- water regulation via the collecting duct
112
Oestrogen- gland and function
Ovary- Inhibits FSH
Stimulates LH
Thickens Uterus lining
113
Progesterone- gland and function
Corpus Luteum-
LH and FSH inhibited
Maintains uterus lining
114
Testosterone gland and function
Testes- forms male secondary characteristics
115
Adrenaline-gland and function
Adrenal gland-
Increase heart rate and breathing for flight or flight mechanism
116
FSH-gland and function
Pituitary gland-
Ovum matures
Follicle develops
117
LH- gland and function
Pituitary gland-
Ovary releases mature ovum into oviduct
Follicle become corpus luteum
118
Hydrogen Carbonate indicator
Co2 presence means it will turn yellow. A lack of it means it turns purple.
119
Photosynthesis starch test
Boil the leaf in ethanol, to remove chlorophyll.
Add drops of iodine.
Blue/Black color indicates Starch presence.
120
How is the response to a shoot of light controlled
Auxin is produced at the tip of the shoot
Auxin diffuses down the shaded side of the shoot
Auxin produces cell elongation
So the cell bends towards the light ]
121
homeostasis definition
The maintenance of a constant internal environment
122
homeostasis 3 examples
sweating
shivering
reducing blood that goes near the skin
123
