Human Bio Unit 2 - Key things Flashcards
What is meant by a phylogenetic relationship?
A relationship based on evolutionary relationship
Homologous chromosomes
A pair of chromosomes having the same gene sequences
Metabolic pathway
Series of chemical reactions
Catalysed by enzymes
The product of one becomes the reactant of the next in the series
A type of gene that may be damaged to produce a tumour cell
Tumour suppressor gene
Types of tumour
Benign
Malignant
What is a species?
Organisms that can breed together and produce fertile offspring
What is a fossil?
Preserved evidence of an organism
“Suggest why studying DNA from fossils allowed scientists to reach conclusions about skin and hair colour”
Order of bases in DNA codes for proteins/pigments for hair and skin colour
What is a tumour?
Mass of cells dividing uncontrollably
Can be benign or Malignant
“How is the spindle formed in mitosis?”
Chromosomes in form of chromatid pairs
Chromosomes attach to spindle
By means if centromere
All at the equator of the cell
Separation of the chromosomes
Spindle pulls chromosomes to the opposite poles of the cell
What is a gene?
Length of DNA
Codes for a protein
By is DNA described as semiconservative?
Each new strand is half of the parent strand
Parent strand acts as template to make the new strand
What is an allele?
Different form of a gene
4 bases
Thymine
Guanine
Adenine
Cytosine
How does crossing over contribute to genetic variability (meiosis)
Part of one chromosome swapped with another
Sections then have new alleles
Causes new combination of alleles
