B1 b2 b3 b4 b5 Flashcards
Advantages of sexual reproduction
Genetic variation . Decreases the extinction due to variation.
Advantages of asexual
One parent needed. Less energy and time.
What happens in meiosis
The chromosomes in the cell doubles. The chromosomes are lined up in the middle and divided. Then they are divided again leaving each cell will 23 chriomsomes and it being genetically different
Structure of dna
DNA is a double helix polymer that contains a base backbone and phosphate. It contains complimentary pairs of a to t g to c which are held together by weak hydrogen bonds.
Mutation
Is a change in the dna base sequence
What can Stem cells do
Differentiate into any cell
Where are plant stem cells found
In the roots and the shoots of the plants where it’s growing
What are adult stem cells used for
Regenerating tissue and repairing damage
Embryonic stem cell
Can differentiate into any cell
Advantages of human genome project
Can help cure inherited diseases and create more medicine
What happens in a mutation
The dna base code changes meaning the amino acids have a different function and shape forming a new protein.cancer can cause ths
What is selective breeding
When you breed 2 organisms with desirable characteristics to create offspring with those traits. This process happens and happened again
Advantages and disadvantage of selective breeding
Advantages-
Offspring’s with desirable characteristics
Disadvantages
Lowers the gene pool no genetic variation meaning it’s easier to kill all the plants
Genetic engineering
Is where you modify genes with a desirable characteristic
Advantages and disadvantages
Advantages-
You will have desirable genes disadvantages-
Might effect our health and is expensive
Physical and chemical defences
Physical
Skin- acts like a barrier
Mucus- traps pathegons
Cilla hair like structure which traps pathogens
Chemicals-
Hydrochloric acid in the stomach that kills pathogens
Lysozymes- in the salvia that break down pathogens
What happens when a pathogen enters the body
The white blood cells produced antibodies. When pathegons enter the body they have something called antigens. The white blood cell will cling onto the antigens killing the pantheon. Memory cells are left in the body so the next time that same pathogen enters the body the memory cells will kill it before it can develop this Is called immunity
BMI
Mass/weight^2
Active transport
Movement of particles across a concerntration gradient from a high concentration to low concentration
Benefits and problems of stem cells
Benefits
Replace damaged cells and damaged body parts
Problems-
Can be rejected.
Religious people believe that it’s the inference of natural orchids
What is the optimum pH of enzymes
7
Cholera
The disease passed throughout water.
Tuberculosis
Bacteria in the air that cause coughing
Chlara ash dieback
Fungi. Can cause leaf loss
