pp 42 2020 Flashcards
Define the term sensitivity [2]
(the ability to) detect stimuli (in the internal / external environment) ; to make (appropriate) responses ;
Define the term sense organ. [2]
groups of receptor cells ; responding to specific stimuli
State the name of the part of the retina labelled X. fig 1.1
fovea
Describe the roles of the ciliary muscles and suspensory ligaments in focusing on a distant object, as shown in Fig. 1.2. [5]
(ciliary) muscles relax ;
suspensory ligaments contract ;
so ligaments pull on lens ;
lens is,flatter;
light is refracted less ;
Describe the changes that occur in the eye when the light becomes bright, as shown in Fig. 1.3. [3]
size of pupil, decreases in bight light;
circular muscles (of iris) contract ;
radial muscles (of iris) relax ;
the change shown in Fig. 1.3 occurs automatically without thought. State the name given to this type of action.
reflex
Fig. 2.1 is a vertical section of a human molar tooth and surrounding structures.
State the names of the parts labelled A
enamel
Fig. 2.1 is a vertical section of a human molar tooth and surrounding structures.
State the names of the part labelled B
dentine
Fig. 2.1 is a vertical section of a human molar tooth and surrounding structures.
State the names of the part labelled C
pulp cavity
Fig. 2.1 is a vertical section of a human molar tooth and surrounding structures.
State the names of the part labelled D
gum
Describe and explain the function of molar teeth. [3]
physical digestion
crushes food
increases surface area of food for chemical digestion
Explain how tooth decay occurs. [4]
food e.g. chocolate remains on teeth
bacteria breakdown sugars
acid is produced
acid dissolves enamel
define herbivore
feeds on plants / producers / / autotrophs
define producer
makes own food / photosynthesis / autotrophic
define a quaternary /4th consumer
feeds on tertiary consumers
define secondary consumer
gets energy from / feeds on, primary consumers / herbivores
State the term given to the group of organisms represented by Z in Fig. 3.2.
decomposers e.g. fungi
Explain, with reference to Fig. 3.2, why food chains usually have fewer than five trophic levels. [5]
small percentage of energy from sun is ’fixed’ by photosynthesis
most energy from sun not available
energy is lost, between trophic levels
energy lost in respiration
would be very small population of predators in fifth trophic level
Intensive livestock production can be damaging to natural ecosystems.
Describe the negative impact on an ecosystem of the intensive production of livestock, such as chickens. [6]
effect of waste (faeces and urine) on, waterways / crops
loss of biodiversity
release of, CO2
named consequence ; e.g. climate change / global warming
providing food for livestock requires monocultures ;
deforestation / habitat loss ;
Forests are cleared for farmland. Deforestation can lead to a loss of soil (soil erosion). Explain the effects of soil erosion on ecosystems. [6]
1 silting of rivers ;
2 landslides / mudslides ;
3 soil does not absorb (rain)water / increased risk of flooding ;
4 increased rate of evaporation / land is exposed to drying ;
5 desertification
6 reduction in transpiration ;
Yeast cells have many structures in common with a plant cell. Fig. 4.1 is a drawing of a yeast cell.
State the names of the cell structures labelled A and D on Fig. 4.1.
A (rough) endoplasmic reticulum ; D (sap) vacuole
State the functions of the cell structures labelled B and C on Fig. 4.1.
B nucleus – store of, DNA ; controls protein synthesis in) the cell ;
C / mitochondrion – (aerobic) respiration ; provides, energy ;
State the name of one structure that is found in plant cells but is absent in yeast cells.
chloroplast
Yeast is used in the production of ethanol to manufacture a type of biofuel.
Fig. 4.2 is a flow chart of the process.
State the names of enzymes S and T.
S – amylase ; T – maltase ;
Complete the balanced chemical equation for anaerobic respiration in yeast.
C6H12 O6 -> 2 (C2H5OH) + 2CO2
Suggest the advantages of using biofuels instead of fossil fuels. [4]
1 conserves fossil fuels ;
2 fossil fuels are not renewable / biofuels are renewable ;
3 maize / plants, uses carbon dioxide (from the atmosphere) ;
less likely to cause acid rain
Fig 4.2 Carbon dioxide may be collected from process U and sold for use in glasshouses. Explain why carbon dioxide is used in glasshouses [5]
1 carbon dioxide is required for photosynthesis ;
2 (more carbon dioxide =) faster rate of photosynthesis ;
3 (more carbon dioxide) more glucose / starch / organic molecules, is produced ;
4 carbon dioxide (concentration) is a limiting factor
5 prevents concentration falling below that of atmosphere
FSH site of production?
pituitary gland
FHS target organ
Ovary
FSH role
(stimulates) development of egg or ovum / ref. to secretion of oestrogen
LH site of production
pituitary gland
LH target organ
ovary
LH role 2
(stimulates) ovulation
/ ref. to secretion of progesterone (and oestrogen) ;
Oestrogen site of production
ovary ; placenta
oestrogen target organ
uterus
oestrogen role
stimulates growth of the lining of the uterus
progesterone site of production
ovary ; A placenta
progesterone target organ
uterus
progesterone role?
maintains the lining of the uterus
Fig. 5.1 shows the changes in the lining of the uterus of a human female.
Describe the changes in the lining of the uterus between days 0 and 7
decrease in thickness ; decreases quickest between days 0 and 3
Fig. 5.1 shows the changes in the lining of the uterus of a human female.
Describe the changes in the lining of the uterus between days 7 and 28 .
increase in thickness ; remains at same thickness from day, 21
Some people are infertile. Artificial insemination (AI) and in vitro fertilisation (IVF) are two methods of fertility treatment. These two methods are outlined in Fig. 5.2.
Describe the similarities between the two processes of fertility treatment shown in Fig. 5.2. [4]
treatment with fertility drugs
(fertility drugs) encourage, follicle production / egg development ;
intercourse does not occur ;
collection of sperm (from a donor)
Some people are infertile. Artificial insemination (AI) and in vitro fertilisation (IVF) are two methods of fertility treatment. These two methods are outlined in Fig. 5.2.
Describe the differences between the two processes of fertility treatment shown in Fig. 5.2. [5]
ovulation occurs in AI
fertilisation in AI occurs inside the body / in IVF it occurs in, a Petri dish or outside the body or A W
eggs removed (from ovary) in IVF
embryo starts development outside body in IVF
embryo inserted into uterus in IVF
State the letter of the DNA base that pairs with A
T
State the letter of the base that pairs with C
G
Outline the roles of DNA in a cell. [3]
store of genetic information
sequence of bases in DNA codes for sequence of amino acids
transfer of information to daughter cells (during mitosis) ;
Cell H in Fig. 6.2 is about to divide by mitosis. State what happens to the chromosomes in cell H before mitosis takes place and state why it is necessary.
each chromosome is duplicatedto maintain the same number of chromosomes
Cell K in fig 6.2 is about to divide into two cells. State the structures that will form between the nuclei so that the cell divides into two cells. [2]
cell membrane ; cell wall
Cell J in Fig. 6.2 is an example of a diploid cell. State what is meant by the term diploid.
(a diploid cell has) two sets of chromosomes
