Evolution + variation ppq's

• Explain why sexual reproduction could produce a new variety of onion.

  fertilisation occurs, so leading to mixing of DNA one copy from each parent gametes produced by meiosis.
• Apple trees can be reproduced so that the apples from the new trees will taste the same as the apples from the parent trees. Give one method used to reproduce apple trees in this way.

  tissue culture
• Give two differences between asexual reproduction and sexual reproduction.

  Asexual involves one parent, No fusion in asexual
• Adult cell cloning is a type of asexual reproduction. Explain why.

  nucleus of egg removed so only one nucleus
• Suggest how scientists could prove that the six types of Island Fox belong to the same species.

  interbreeding, successful between different island types
• The sequence of compounds A, C, G and T in the gene is important.


  Explain why.code for sequence of amino acids code for a specific protein
• When Mendel published his work on genetics, other scientists at the time did not realise how important it was.


  Suggest two reasons why.didn't know about chromosomes

  had preconceived theories
• How could the Island Fox have developed into a completely different species from the mainland Grey Fox?

  (two ancestral populations) separated by geographical barrier. Genetic variation under different environment. Better adapted to survived to reproduce so more favourable alleles
• Suggest why the Island Foxes have developed into different varieties of the same species instead of six different species.

  continued to mate with each other, few beneficial mutations.
• what is a plasmid?

  DNA, circular
• Why did the scientists add kanamycin to the agar jelly (Step 4)?

  kills any cells not having Kan' gene hence surviving cells will also contain Bt' gene .
• Mendel thought that the production of a large number of offspring plants improved the investigation.

  Explain why.fertilisation is random

  anomalies have been eliminated
• DNA is a polymer made up of repeated nucleotides Name the units that make up the nucleotide


  base

  phosphate group

  sugar
• An allele that is expressed only when two copies are present is called

  recessive allele
• A genotype in which two alleles for the characteristics are identical.

  homozygous
• Term genome


  entire DNA of an organism
• A gene is a length of DNA. What type of substance does a gene code for?

  protein
• What is the name of the type of cell division that produces sperm cells?


  meiosis
• Describe the shape of a DNA molecule.

  double helix, long
• Suggest one advantage of having DNA analysis.

  help treatment
• Why is DNA described as a polymer?

  many (joined) nucleotides or monomers
• Describe the structure of a nucleotide.

  phosphate

  (phosphate attached to a) sugar

  (which has 1 of 4) base(s) (attached to sugar)

  (bases) are A, C, G and T
• Describe how non-coding parts of DNA can affect the expression of genes.

  can switch genes on/off
• Describe three differences between the processes of mitosis and meiosis.

  1. mitosis produces two (daughter) cells but meiosis produces four (daughter) cells

  2. one cell division in mitosis but two cell divisions in meiosis

  3. mitosis produces genetically identical cells, but meiosis produced genetically different cells
• Describe one similarity between the processes of mitosis and meiosis.

  DNA doubles
• Why are the children not genetically identical?

  genes from different parents

  different egg
• Give two benefits of understanding the human genome.

  - Tracing human migration patterns

  - Diagnosis of inherited disorders
• Give reason for each step:

  1. Several groups of cells are scraped off the leaf:

  2. Nutrients are added to the agar jelly

  3. Hormones are added to the agar jelly:

  4. The plant cells are kept in sterile conditions:

  5. The plant cells are kept at 20 °C:

  1. so many / several plants can be produced

  
  

  2. for making protein

  
  

  3. so differentiation occurs

  
  

  4. prevent disease

  
  

  5. so optimum / good growth
• Explain why sexual reproduction is an advantage for bluebells.

  genetic variation (in offspring)

  (so) better adapted survive

  can escape adverse event in original area (by living in new area)

  many offspring so higher probability some will survive
• Suggest one way that classification systems are useful to scientist


  to know which species are closely related
• How does the fossil records provide evidence for Darwin's theory of evolution

  older fossils have a simpler structure
• what is a gene made of

  small section of DNA
• What is one reason, other than collisions with an asteroid, why groups of animals may become extinct?

  Loss of habitat
• What is another reason, other than collisions with an asteroid, why groups of animals may become extinct?

  new predator

  competition for food

  new disease
• How do we know what types of animals lived hundreds of millions of years ago

  fossils
• How many years ago did the most recent mass extinction of animals occur

  65 million years ago
• Why are scientists not sure how many groups of animals became extinct in themes recent mass extinction

  fossil records are incomplete

  not enough evidence
• Suggest how problems caused by selective breeding in cows can have negative financial effects for the farmer

  Higher veterinary costs, less income from sale of milk and meat productsSee an expert-written answer!We have an expert-written solution to this problem!
• Give two ways fossils are formed

  footprints

  animal body covered in sediment
• How can fossils give evidence for evolution

  fossils show change over time