b1
- Created by: bwillows1
- Created on: 11-05-14 10:48
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- B1
- genes chromosomes and DNA
- most cells in body have nucleus
- containing genetic material
- arranged in chromosomes
- 23 pairs
- each chromosome is 1 long molecule of DNA
- coiled up
- gene is a short length of a chromosome
- arranged in chromosomes
- containing genetic material
- genes can exist in different versions
- each version = different characteristic
- different versions of the same gene = ALLELES
- control development of characteristics
- each version = different characteristic
- each gene is a code for making a certain protein
- proteins are building blocks of cells
- having different proteins = different characteristics
- STRUCTURAL PROTEINS
- part of things like skin/hair/blood/ cytoplasm in cells
- e.g collagen = structural protein found in tendon/bone & cartilage
- part of things like skin/hair/blood/ cytoplasm in cells
- FUNCTIONAL PROTEINS
- E.g - enzymes are proteins that help with digestion by breaking down food molecules
- amylase breaks down starch to maltose
- E.g - enzymes are proteins that help with digestion by breaking down food molecules
- proteins are building blocks of cells
- an organisms genotype is all the genes it has
- characteristics and organism displays is its phenotype
- some characteristics are controlled by only genes
- eye colour
- dimples
- some characteristics are only controlled by environment
- scars
- some caused by both
- weight
- some characteristics are controlled by only genes
- characteristics and organism displays is its phenotype
- most cells in body have nucleus
- genes and variation
- sex cells have 23 single chromosomes
- alleles are different versions of the same gene
- children resemble both parents
- not identical to any
- 2 chromosomes in a pair are never identical because of different alleles
- when people produce sperm and egg cells their pairs of chromosomes separate and go into different cells.
- sex cells produced by individuals are genetically different
- variations
- sex cells produced by individuals are genetically different
- when people produce sperm and egg cells their pairs of chromosomes separate and go into different cells.
- inheritance and genetic diagrams
- combination of alleles determines phenotype
- 2 of same gene (1 from each parent)
- HOMOZYGOUS
- 2 alleles of the SAME gene
- HETEROZYGOUS
- 2 DIFFERENT alleles for the gene
- alleles can be dominant or recessive
- characteristics caused by dominant alleles will be shown
- DOMINANT
- capital
- recessive
- lower case
- DOMINANT
- characteristics caused by dominant alleles will be shown
- combination of alleles determines phenotype
- genetic diagrams and sex chromosomes
- punnet squares
- men
- XY
- Y chromosome gives male characteristics
- XY
- women
- **
- the gene that makes embryo into a male causes a specific protein to be formed
- causes development of testes
- testes produces male sex hormone
- in females the protein is not produced
- formation of ovaries
- causes development of testes
- genetic disorders
- some inherited
- one or both parents carry faulty allele and pass it on to their children
- caused by faulty alleles
- Cystic fibrosis and huntingtons are both caused by faulty alleles of a single gene
- cystic fibrosis
- caused by recessive alleles
- genetic disorder of the cell membranes caused by faulty recessive alleles.
- symptoms
- thick sticky mucus in air passages, gut and pancreas
- breathing difficulty
- chest infections (painful coughing)
- difficulty in digesting food
- because it is recessive, people with only 1 copy of the allele wont show symptoms
- CARRIERS
- both parents must be characters or sufferers for child to get disorder
- CARRIERS
- caused by recessive alleles
- Huntingtons
- caused by a dominant allele
- means 50% chance of each child inheriting disorder if 1 parent is carrier
- carrier parent with of course be a sufferer because allele is dominant
- late onset, after age of 40
- carrier parent with of course be a sufferer because allele is dominant
- means 50% chance of each child inheriting disorder if 1 parent is carrier
- caused by a dominant allele
- cystic fibrosis
- Cystic fibrosis and huntingtons are both caused by faulty alleles of a single gene
- some inherited
- genes chromosomes and DNA
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