Bio P2 Flashcards
(36 cards)
Name the common defect of the eye which causes distant objects to appear out of focus
Myopia
Describe how the brain receives information about light entering the eye
-Cells in the retina sensitive to light
-Cause for an electrical impulse to be passed along a neurone
-Along the optic nerve
Describe how microorganisms in layers of soil help recycle chemicals in dead plants (Compost)
-In microorganisms digestion occurs
-Through secretion of enzymes
-This releases mineral ions
-These organisms also respire
-Which leads to the production of carbon dioxide
Describe how chemicals, from decomposed microorganisms, are used again in plants
-Carbon dioxide gets taken in the plants
-By diffusion into the stomata
-Carbon dioxide is used in photosynthesis to make glucose
-The ions are taken into the roots by active transport
-Nitrate ions make ammino acids
-Phosphates for DNA
Give 2 abiotic factors of an ecosystem
-Soil pH
-Soil temperature
Give 2 biotic factors of an ecosystem
-Food
-Predators
Give 2 ways in which a person can reduce the likelihood of developing type 2 diabetes
-Exercising more
-Having less carbohydrates in your diet
Explain the effect a high concentration of insulin has on blood glucose concentration
-It would lower blood-glucose levels
-Glucose is converted into glycogen
-By the liver
Name 3 harmful substances that cause water polllution
-Fertillisers
-Herbicides
-Toxic chemicals
Describe how substances that pollute the air could be harmful to humans and other organisms (6)
-Carbon dioxide and greenhouse gases contribute to global warming
-This leads to a loss of habitat as sea levels rise
-Acidic gases like sulfur dioxide damage leaves which means less photosynthesis
-It damages roots so less ions can be absorbed
-They can also provide respiratory problems too
-Carbon monoxide binds to haemoglobin and prevents oxygen from being carried the body
-Soot can darken leaves which prevents photosynthesis from being carried out
Describe how substances that pollute the water could be harmful to humans and other organisms (6)
-Sewage means that bacteria multiply which uses oxygen in respiration so water animals cannot respire
-It may also cause pathogens in water
-Fertilliser means that algae multiply and algae block light so plants cannot photosynthesise
-And a lack of oxygen for respiration so fish die
-Acid rain lowers pH of water which damages fish gills and bleaches coral
-Plastics block light so less plants can photosynthesise
-Oil can damage birds feathers which prevents them from flying
Give 2 uses of water in plants
-Photosynthesis
-Transpiration stream
Give 2 disadvantages of rearing cows indoors
-Cost of heating
-Diseases can spread easily
What is the name given to all of the organisms living in the same habitat?
A community
Suggest one advantage of growing plants that are genetically identical together?
Have the same desireable characteristics
Describe how carbon in leaves is recycled and used again
-Microorganisms cause decay
-Enzymes are used in decay
These microorganisms respire which releases carbon dioxide into the air
-Carbon dioxide is taken into the leaves via the stomata
-This is used in photosynthesis to make glucose
Describe how nitrogen in leaves is recycled and used again
-Once decomposed the nitrates are released into the soil
-Nitrate ions are taken in to the plant by the roots
-By active transport
-To make amino acids
Explain why the change in chromosome number is important in meiosis (3)
-Meiosis forms gametes
-2 gametes fuse
-This keeps the chromosome number constant for generations
Describe how meiosis makes cells that are genetically different (2)
-Random chromosome from each pair
-Moves to one end of the cell
Explain how our understanding of evolution has developed due to fossil evidence
-Fossils show evidence of life in the past
-fossils show change over time
-fossil record shows development of species over time
- fossils show evidence of extinction
-fossil record shows how organisms from the past are related to species alive today
-There are still gaps in fossil record
-gaps in fossil record are being filled in with new evidence
Explain how our understanding of evolution has developed due to our understanding of genetics
-Mendel’s breeding experiments with plants
-Mendel’s description factors of inheritance
-dominant and recessive alleles
-observation of chromosome behaviour during cell division
-chromosome behaviour and Mendel’s units work in similar ways
-structure of DNA worked out
- gene mechanism in determining protein synthesis worked out
-genetic variation in a species - variation due to mutation or change in gene
-individuals with advantageous characteristics more likely to
survive
-individuals with advantageous characteristics more likely to reproduce
-survivors pass on advantageous alleles - eg of evolution(such as antibiotic resistance in bacteria
-new species arise when sufficient changes occur to prevent (successful) reproduction
Suggest why a fermenter requires a cooling oil
As the heat could kill the fungus
What conditions are needed for mycoprotein growth
-Aerobic conditions
-Glucose syrup
Give 2 control variables in the milk decay practical
-Volume of milk
-Freshness of the milk
