Biology section 6 Knowledge organizer Flashcards
Number of cells made by Mitosis
2
Number of cells made by meiosis
4
Variation in cells produced by mitosis
genetically identical to each other and the parent cell
Variation in cells produced by meiosis
different to each other and parent cell
What is the purpose of mitosis
Grow , repair , asexual reproduction
what is the purpose of meiosis
produce gametes for sexual reproduction
number of chromosomes in cell after mitosis
Full amount(pairs of chromosomes)
number of chromosomes in cell after meiosis
Half (single chromosomes)
What is an advantage of sexual reproduction
Produces variation. offspring are more likely to survive changes to the environment and dieses
What is an disadvantage of sexual reproduction
Requires a mate. slower way of producing offspring
What is an advantage of asexual reproduction
Produce lots of offspring quickly. no mate needed
What is an disadvantage of asexual reproduction
Offspring are less likely to survive environmental changes and disease
What is a symptom of polydactyly
Extra fingers and toes
What is a symptom of cystic fibrosis
Disorder of cell membranes. causes sticky mucus on lungs
What is polydactyly caused by
Dominant allele
What is the genotype of people with polydactyly
PP or Pp
What is the genotype of people without polydactyly
pp
Does polydactyly have carriers
No
What causes cystic fibrosis
Recessive allele
What is the genotype of people with cystic fibrosis
cc
What Is the genotype of people without cystic fibrosis
CC or Cc
how many chromosomes does a human chromosome have
23 pairs
Does cystic fibrosis have carriers
Yes genotype Cc
What chromosomes do males have
XY
What chromosomes do females have
XX
What causes antibiotic resistant bacteria
Mutations
Antibiotics
Breeding and spread
How can we reduce the spread of arb
Only prescribe to serious bacterial infections
Complete a full course of antibiotics
Restrict antibiotic use in agriculture
Explain Darwin’s theory
- There is variation in a population caused by mutations to their genes
2.There is competition between individuals
3.The better adapted organisms survive breed and pass on their alleles - Over time the number of individuals with better adapted alleles increase
How are fossils formed
Parts of an organism dont decay
hard parts of an organism are replaced by minerals as they decay
traces of organisms are preserved
What do fossils show us
How organisms have changed over time and provide evidence for evolution
Explain the process of selective breeding
- Choose parents with the correct characteristics from the population
- Breed them together
- Choose the offspring with the desired characteristics and breed them together
4.continue through multiple generations
Give examples of desired characteristics
Disease resistance in food crops
animals which produce more meat or milk
domestic dogs with a gentle nature
large or unusual flowers
Give the positives and negatives of GM crops
+ increases yield of crops
- could negatively effect wild populations of flowers and insects
- Effects on human health not fully explored
What is the process of genetic engineering
- genes are cut out by enzymes
- the gene is inserted into a vector
- the vector is used to insert the gene into the required cells
4.Genes are transferred to the cells of animals, plants or microorganisms at an early stage in their development so that they develop with desired characteristics
Give examples of genetic engineering
Insulin gene
making plants resistant to disease, insects or herbicides
