B6-inheritance,variation And Evolution Flashcards
What is the structure of a DNA molecule
Double helix
Two strands
What is a gene
Small section of DNA found on a chromosome
What is a genome
Entire set of genetic material in an organism
What does sexual reproduction produce
Genetically different cells
What does asexual reproduction produce
Genetically identical cells ( clones )
How gametes produced
Meiosis
How many cells does meiosis produce
Produces cells which have half the normal number of chromosomes
What chromosomes does males have and what causes male characteristic to develop
XY chromosome
Y chromosome causes male characteristics
What chromosomes does females have and what causes male characteristic female characteristics to develop
XX chromosomes
XX combination allows female characteristics to develop
What are two recessive or two dominant alleles called
Homozygous
What is 1 dominant and 1 recessive allele called
Heterozygous
What is polydactyly cause by
Dominant allele
What is cystic fibrosis cause by
Recessive allele
What is a genotype
An organisms specific genetic code
What is a phenotype
How this code is expressed in physical characteristics
Reasons for embryonic screening
It will help stop people suffering
Treating disorders costs the government a lot of money
There are laws to stop it going too far
Reasons against embryonic screening
Can increase prejudice
Expensive
Everyone may want to screen their embryos so they can pick the most desirable one
What are ways extinction happens
Environment changes too quickly
New predator kills them all
New disease kills them all
Can’t compete with other species for food
Catastrophic event
What is Charles Darwin’s theory about evolution
The organisms with the most suitable characteristics for the environment would be more successful competitors and more likely to survive, this means they are more likely to reproduce and pass genes on to their offspring.
The organisms that are less well adapted would be less likely to survive and reproduce
What is selective breeding
When organisms are deliberately bred so their offspring have the desirable characteristics
What is genetic engineering
To enhance or modify the characteristics of an individual organism
What is process of selective breeding
1.select animals with characteristics you want
2.breed them together
3.select the best of the offspring and breed them together
4.repeat process over generations
What is the 3 domain system
Archaea - primitive bacteria
Bacteria - true bacteria
Eukaryota - broad range of organisms
Why are fossils used
As evidence of organisms existence
Which domain is fungi classified in
Eukaryota
Which two characteristics are features of organisms in the domain archaea
Can survive in extreme environments
Cytoplasm contains dna
Give three types of evidence that are used now to classify living things
Chemical analysis
DNA analysis
Study of cell structures with light microscopes
Describe evidence that would show two individual organisms ( like birds) are the same species
Similar/same phenotype
Similar/same genotype
Produce fertile offspring
If a table has no results that are the same why can the mode not be determined
No results occur more than once
Explain how the effect of adrenaline on heart rate might cause reaction time to decrease
Causes heart rate to increase
Which increases oxygen
which increases rate of respiration
So releasing more energy for muscle contraction faster
Suggest why reaction time decreases when caffeine binds to adenosine receptors
Adenosine has no effect on relay neurone
Impulses in relay neurone are faster
Explain how polydactyls occurs
Caused by dominant allele
Caused by mutation
During meiosis
Causing a change in amino acid sequence
