Biology Paper 2 Flashcards
Describe how you test a leaf for starch
Place leaf in hot ethanol in water bath
Use iodine solution
If starch present = leaf goes blue/black
Structure of Palisade Mesophyll
Cells tightly packed/elongated
Cell contain chloroplasts
Palisade mesophyll contains lots of chloroplasts
Chlorophyll absorb sunlight for photosynthesis
Structure of Spongy Mesophyll
Contains air spaces and gaps
Spongy cells are irregularly arranged
Diffusion occurs in spongy mesophyll
Spongy mesophyll in lower surface of leaf
Where is stomata on surface of a leaf
In lower surface of leaf
No stomata in upper surface
How is protein made in a cell
Transcription occurs
mRNA leaves nucleus
Enters cytoplasm and ribosomes
tRNA bring attached amino acids
For complementary base pairing
Translation occurs
Where does ultrafiltration take place in nephron
Bowman’s capsule
Where does reabsorption of glucose take place in nephron
PCT
Which part of nephron responds to a change in ADH
Collecting Duct
Function of collecting duct
Water reabsorbed
via osmosis
So less water in urine
FSH function
Pituitary gland: Stimulates follicle growth
Lowest peak on a graph
LH function
Pituitary gland: Ovulation
Highest peak on graph
Oestrogen function
Ovary: Repairs uterus lining
Peak left of highest peak on graph
Progesterone function
Ovary: Maintains uterus lining
Highest peak at day 21 on a graph
4 ways alveoli adapted for maximum gas exchange
1 cell thick
High concentration gradient
Contain moisture and water
High surface area to volume ratio
Give a method to sterilise without killing cells
Alcohol
Why can’t animal tissue grow into new individuals via micropropagation
Cells are specialised
Only one cell type present
No stem cells present
Describe how the nephron absorbs glucose back into the blood from
the filtrate.
Selective reabsorption
In PCT
Via active transport
Tube transporting
urine to bladder
Ureter
Explain how the pituitary gland and the nephron cells will
respond in a patient who is dehydrated
Lower Water Potential in Blood
Pituitary gland release more ADH
Collecting duct more permeable
More water reabsorbed
Urine more concentrated
Label A,B,C,D,X
A = Retina
B = Conjunctiva
C = Cornea
D = Lens
X = Iris
Eye in Bright Room
Circular muscles contract
Radial muscles relax
Pupil constricts
Describe how a farmer could use selective breeding to increase the height
of cattle.
Select cattle that taller and mate them
Select offspring taller and mate them
Repeat through generations
Explain why micropropagation was used to produce copies of the transgenic
soya plant.
Plants genetically identical
All have same of (specific characteristic)
Fast Method
Explain energy content practical
Ignite chip and hold under test tube
Keep igniting till chip burnt completely
Measure Change in Temp
Repeat three times
Same mass of banana chips
Same volume of water
Insulation prevents…
heat loss
Oxygen supplies ensure…
complete combustion occurs
Explain the negative effects of an increase in atmospheric carbon dioxide gas
Cause greenhouse effect
Ice cap melting
Ocean acidification
Describe the role of microorganisms in the conversion of organic waste into
nitrate ions in the river
Decomposers
Convert organic waste to ammonia
Nitrification occurs
Convert nitrites into nitrates
Which groups of microorganisms include pathogens
bacteria, fungi, protoctista and virus
Explain how the rabies vaccine prevents dogs from developing rabies
Antigens in vaccine
Lymphocytes recognise antigens
Memory Cells made
So antibodies made faster when virus encountered
Describe how the cells use the RNA to produce the viral proteins
Ribosomes bind to DNA
Translation occurs
Codon on RNA codes for amino acid
tRNA binds to RNA
tRNA brings amino acids
Amino acids join together to make protein
Explain why producing genetically engineered plants with additional suberin in
their roots could reduce atmospheric carbon dioxide
Plants absorb CO2
For photosynthesis
CO2 stored as suberin
Less CO2 released from decomposition
Transgenic means
Cell/Organism undergone genetic modification - genes transferred from unrelated organism
Give three reasons why the scientists use micropropagation to reproduce the
transgenic crop plants
Prevent water loss
Due to osmosis
When water moves from high to low water potential
Suggest why the student poured water through the soil samples for five
minutes before adding the ammonium salts
Wash away nitrate
Nitrate made from ammonium salt
So test is fair
In nephron protein doesn’t pass out of what?
Glomerulus
Too large
Beta thalassaemia is a genetic condition caused by a mutation in a gene
for haemoglobin.
People with beta thalassaemia produce less haemoglobin and fewer red blood cells
than people without the condition.
(a) Explain why people with beta thalassaemia may experience severe tiredness.
Less oxygen transported to muscles
Less respiration
DNA strand
A-T
C-G
DNA-RNA strand
A-U
C-G
Protein synthesis of the modified gene will produce haemoglobin.
Describe the stages of this protein synthesis
Transcription occurs in nucleus
Production of mRNA
Translation occurs - mRNA bind to ribosome
tRNA brings amino acids
Codon binds to anticodon
Triplets on tRNA and mRNA bind
Enucleated Meaning
Nucleus Removed
Explain importance of cell differentiation in development of growing embryo
Unspecialised cells develop into specialised cells
Cells with specific functions
To produce tissues/organs
Explain issues between adult stem cells and embryonic stem cells for treatment
Cells from embryo can make any cell type
Ethical issues from using embryonic stem cells
Describe role of bacteria in nitrogen cycle
Nitrogen Fixation - nitrogen gas to ammonia
Nitrification - Nitrite to Nitrate
And Ammonia to Nitrite
Denitrification - Nitrate to Nitrogen Gas
Describe how mammal is cloned
Use enucleated egg
Fuse adult cell with empty egg
Use of electricity for shock
Cell division mitosis occurs
Forms embryo
Place in uterus womb of surrogate mother
Eye far object
Ciliary muscles relax
Suspensory ligaments
Refracts by smaller amount
