Paper 1 Flashcards
(28 cards)
Describe purpose of coronary arteries
to provide oxygen ti the heart muscles
oxygen used in respiration to rekease energy
what do the coarse and fine adjustment knobs do
coars moves the stage
fine brings cells/image into clear focus
how do bacteria multiply
binary fission (simple cell division)
describe adaptations of a nerve cell
axon (carries electrical impulses around body) is insulated by a myelin sheath
-speeds up transmission of nerve impulses
end of axon has synapses- allows impulse to pass from one nerve cell to another
cell body of nerve cell has dendrites
-increase sa so other nerve cells can connect more easily
describe adaptations of muscle cells
contain protein fibres which shorten, decreasing kength of cell when muscle contracts
have lots of mitochondria to provide energy for muscle contraction
describe adaptations of xylem
very thick walls containing lignin
-provides support to the plant
-causes xylem cells to die as they are sealed with lignin
no end walls
-so water and dissolved minerals can flow easily
no internal structures
-easier for water and minerals to flow
describe adaptations of phloem
end walls have pores
-sieve plates
-allow sugars to move through cell interior
companion cells connected by pores
-mitochondria in companion cells provide energy to phloem vessel cell
3 stages of cell cycle of mitosis
- dna replicates to form 2 copies f each chromosome, internal structures are also copied and cell grows
- mitosis, one set of choromosomes pulled to each end of the cell, nucleus divides
3.cytoplasm and cell membrane divide to form 2 identical cells
functions of mitosis
-growth and development of multicellular organisms
-when organism repairs itself
-asexual reproduction
Describe how oxygen gets into fish body
Describe adaptations of fish gills
-oxygen-rich water passes into the mouth, then flows over gills where oxygen is transported into blood stream
-gills are covered in karge number of fine filaments when gases pass in and out of blood
-deoxygenated blood passesninto filament and oxygen diffuses from eater to blood
-blood returns to body
Adaptations:
-massive sa:vol
-filaments have thin membrane for a short diffusion distance
-filaments have efficient blood supply to take oxygenated blood away to ensure concentration gradient remains high
Describe how to prepare a food sample for a food test
1.grind food sample with distilled water using mortar and pestle to make a paste
2.transfer is beaker and add more distilled water, stir to dissolve food in water
3.filter solution to remove suspended food particles
purpose of plasma
transports substances round body
-glucose from small intestine to other organs
-co2 from aeobic respiration frommorgans tonlungs
-urea from liver to kidneys
Donated blood in medicine..
1.to replace blood lost during injury
2.some people giving platelets extracted from blood to help clot
3.proteins extracted from blood can be useful fir example antibodies
what liquid is added to tube in photosynthesis rpa and why
sodium hydrogen carbonate solution because it releases carbon dioxide
list factors which affect the rate of transpiration
Higher when:
-temp is higher
-dry conditions (air less humid)
—because evaporation takes place more quickly under dry conditions
-windy (removes water vapour, allowing water to evaporate)
-light intensity increases, stonata open
Describe phagocytosis
-white blood cell ingests/engulfs pathogen
-white blood cell releases enzymes to destroy pathogen
Define antibodies
give 2 features
protein molecules produced by white blood cells which stick to pathogens and triggers them to be destroyed
-extremely specific
-can remain in blood for a long time
How do antitoxins work
White blood cells can produce chemicals called antitoxins
These stick to toxin molecule and prevent them from damaging cells
What do aphids do
extract nutrients such as sugars from the plant, stunting its growth
Plant ion deficiencies
-lack of nitrate ions
-means stunted growth
(nitrate needed for protein synthesis therfore growth)
-lack of magnesium ions causes chlorosis
-because magnesium is rewuired to make chlorophyll
List 5 uses of glucose from photosynthesis
- to release energy is respiration
2.produce insoluble sotrage molecule starch
3.coverted into fats and oils as a storage form of energy
4.cellulose made from glucose produced in photosynthesis
5.reacted with nitrate ions to produce amino acids which are used by plant to synthesise proteins
Define metabolism
the sum of all chemical reactions in cell or body
Lipid synthesis
1 glycerol molecule + 3 fatty acid molecules produces lipid found in cell membrane
List reasons why humans need energy
for movement
to keep warm
for chemical reactions to build larger molecules
