Paper 42 2021 Flashcards
Name 3 parts of the small inestine
ileum
villi in ileam
duadenum
Describe how active transport differs from diffusion. [4]
membrane for active transport uses (chemical) energy
energy from, the cell / respiration / mitochondria
(substances move) against concentration gradient / low to high concentration
using / AW, proteins / carriers (in membranes)
Explain the importance of the microvilli in small intestine [2]
idea of more (cell) membrane / large surface (area)
allow, increased rate of / fast, absorption (of nutrients)
Goblet cells provide protection for the epithelial cells that line the intestine.
State the name of the protective substance produced by goblet cells
mucus
Goblet cells provide protection for the epithelial cells that line the intestine
Suggest why a protective substance is necessary in the intestines. [3]
to protect the intestine from) bacteria pathogens
protects intestine from enzmes and self digestion
protects fom hydrochloric acid
Describe the roles of lacteals in the centre of each villus 2
absorbs, fats / fatty acids (and glycerol)
transports, fats / fatty acids, into, lymphatic vessels
identify the level of organisation of gall bladder
organ
identify the level of organisation of endoplasmic reticulum
cell structure
identify the level of organisation of intestinal epithelium
tissue
identify the level of organisation of the ileum
organ
refer to question 1 f
State what conclusions can be made about the enzymes in the fungal extract and give evidence from Fig. 1.3 to support your conclusions. [7]
conclusions
1 fungal extract contains amylase and pectinase ;
6 D / fungal extract, in both Petri dishes has clear zones (MP1) ;
2 clear zone is where substrate has been, digested / broken down ;
7 no staining in clear zones shows that enzyme was active (MP2) ;
5 extract has, higher concentration of / more, amylase than pectinase ;
10 clear zone in, D / with fungal extract, is larger in the plate containing starch than in the plate containing pectin (MP5) ;
13 no clearance / no breakdown / no change, with water
refer to question 1 f
The investigation was repeated but at 5°C instead of at 27°C. Predict the effect of the lower temperature on the results
(same pattern but) smaller / no, clear zones
Define the term chromosome. 2
(thread-like structure) molecule, of DNA ;
contains, genes / alleles / genetic information or material ;
refer to question 2 a
Suggest why the scientist placed a bag around flower 1.
prevent pollination (from another flower or plant) / to prevent (other) pollen landing on stigma
refer toquestion 2 a
Explain how sexual reproduction results in the variation that the scientist discovered in the offspring plants. 2
different, combinations of, maternal and paternal chromosomes
fusion of gametes with different, genotypes or alleles
Explain how the chromosome number is maintained from one generation to the next 2
meiosis halves the number of chromosomes
diploid, number is restored at fertilisation
define phenotype 2
observable feature of an organism
phenotype of an organism depends on the genotype
define Genotype
genetic make-up of an organisms in terms of alleles present
refer to question 2 b i
PRPR ;
PRPW ;
PRPR,
PRPW,
PWPW
refer to question 2b
State the type of inheritance that is shown by petal colour in C. japonica.
codominance
Fig. 3.1 shows the changes in the concentrations of the hormones FSH and LH during a menstrual cycle.
Suggest the target organ for FSH.
ovary
State how FSH reaches its target organ [1]
plasma / blood (vessels)
what does FSH stand for
Follicle-stimulating hormone
what does LH stand for
Luteinizing hormone
Describe the relationship shown by the two hormones in Fig. 3.1 [3]
2 both hormones reach a peak at, day 14 / the same time / the same day ;
3 LH starts increasing before FSH ;
4 LH has a higher concentration than FSH at, the peak / day 14 ;
Describe the roles of FSH in the menstrual cycle. 4
any four from:
1 FSH stimulates, development of follicles (in ovary) ;
2 FSH stimulates, development of, ovum
3 FSH stimulates, production of oestrogen (from ovary) ;
4 (FSH and) LH (surge) stimulates, ovulation
Describe the changes that occur in the lining of the uterus during one menstrual cycle. [3]
1 loss / thinning, of lining (of uterus), during first week
2 thickening of, lining (of uterus), during second week
3 thickness of lining remains constant, in the last two weeks if no fertilisation ;
Oral contraceptives are a method of birth control taken by women. Outline how the hormones in contraceptives act as a method of birth control. [4]
1 (contraceptives contain) progesterone (with oestrogen) ;
2 decreases secretion / prevents release, of FSH / LH ;
3 prevents, development / maturation of, follicles / eggs / ova ;
4 prevents ovulation / described
refer to figure 4.1
what conducts impulses to central nervous system (CNS)?
state letter on fig
afferent, neurone V
refer to figure 4.1
what conducts impulses to an effector
state letter on fig
motor neurone Y
refer to figure 4.1
conducts impulses only within the CNS
state letter on fig
relay neurone X
refer to figure 4.1
detects / senses, stimulus / change in temperature
state letter on fig
receptor U
refer to figure 4.1
contracts / causes movement / carry out response
state letter on fig
biceps / muscle / effector Z
Fig. 4.2 shows the structure of the synapse at W on Fig. 4.1.
Describe how an impulse travels across the synapse shown in Fig. 4.2. 5
1 vesicles move towards end of, pre-synaptic neurone / axon / AW ;
2 vesicles fuse with (pre-synaptic) membrane ;
3 neurotransmitter diffuses across, synapse / gap / synaptic cleft ;
4 neurotransmitter binds to receptor, on post-synaptic neurone ;
5 impulse (generated) in post-synaptic neurone ;
State examples of a reflex action that occurs in the eye. 6
blinking / pupil reflex / iris reflex / accommodation / corneal reflex / tear reflex
State two factors that affect the volume of urine produced in the human body
any two from: water / fluid / liquid, intake ; exercise / activity level ; sweating ; temperature ; salt / salty food, intake ; quantity of urea produced / concentration of urea in blood ; (named) drug ; (named) medical condition ;
Nitrogen is an important element for organisms. In a livestock farm, waste from animals contains protein. This waste is often spread on farmland as a fertiliser. Describe how the nitrogen in protein is recycled in the soil into a form that plants can absorb and use. [6]
any five from:
1 protein, broken down decomposed, to amino acids ;
2 ammonification
3 amino acids converted to, ammonium (ions) / NH4+ ;
4 ammonium (ions) convert to nitrate (ions)
5 nitrification / nitrifying bacteria ;
6 plants, absorb nitrate (ions) (and ammonium ions)
Waste from livestock farms often pollutes water courses, such as streams and rivers, leading to a reduction in biodiversity. Explain how the pollution of water courses by animal waste leads to a reduction in biodiversity [6]
any six from:
1 eutrophication ;
2 increased growth of, plants / producers / algae ;
3 plants / producers, compete with each other for light / AW
reasons for reduction in biodiversity:
8 death of, fish / invertebrates (due to lack of dissolved oxygen) ;
9 decrease in, food / energy, available in, ecosystem / AW ;
11 ref to aerobic respiration (in either section)
Enzymes are catalysts. Define the term catalyst. [2]
(substance) that increases the rate of (chemical) reactions ; not changed, during / by, the reaction ;
Fig. 6.1 shows diagrams of three enzymes and eight different substrates.
State the letter of the substrate that will be broken down by enzyme 1.
T
Fig. 6.1 how do you know T is broken down b 1 [2]
T) fits into, enzyme ;
active site has a complementary shape (to T)
what reaction does maltase catylise
breakdown of maltose to glucose
what reaction does protease catylise
breakdown of proteins to amino acids
what reaction does lipase catylise
breakdown of fats to fatty acids and glycerol
what reaction does lactase catylise
breakdown of lactose to simpler sugars
what reaction does( DNA) ligase catylise
insertion of a short length of DNA into a plasmid
what reaction does restriction enzyme catylise
digests, DNA molecules
Describe the roles of LH in the menstrual cycle. [2]
1 (FSH and) LH (surge) stimulates, ovulation
2. Stimulates corpus luteum/ release, of progesterone
