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42 Cards in this Set
- Front
- Back
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DNA |
DeoxyriboNucleic Acid
Found in the nucleus in long structures called chromosomes
Polymer Made up two strands coiled together in the shape of a double helix coiled together in the shape of a double helix
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Gene |
Small section of DNA found on a chromosome
Each gene codes for a particular sequence of Amino acids which are put together to make a specific protein
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Genome |
Entire set of genetic material in an organism |
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Why is understanding the Humane Genome important? |
•Allows scientists to identify genes that are linked to diseases/inherited diseases - Understand disease better - Develop effective treatments
•Trace migration of certain pop.
All humans have common ancestors who lived in Africa
HG is mostly identical but as different pop. migrated away from Africa, tiny difference in genomes developed
Scientists can work out when new pop. split off in different direction and what route the took by investigating
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Structure of DNA |
Made up of repeating units called Nucleotides
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Nucleotides consist of? |
One sugar molecule One phosphate molecule One "base" |
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Sugar and Phosphate molecule |
Form a "backbone" to DNA strands |
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Bases |
A T G C
Order of bases decides order of Amino acids in a protein
Each Amino acid coded by a sequence of 3 bases in a gene |
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Complementary pairing |
A-T G-C |
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mRNA |
Carries code to make proteins to Ribosomes
1) Proteins made on tiny structures called Ribosomes 2) DNA code in nucleus and can't move out bc of it's size
3) Molecule mRNA copies code from DNA
4) Carries the Amino acids in the correct order to the ribosomes to produce the protein
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Mutations |
Changes to the Genetic code Due to exposure to some types of radiation or certain substances |
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Mutation effect on proteins? |
Most have very little or no effect on protein
But sometimes, could affect its ability to perform it's function
1) Enzymes active site is denatured
2) Structural Proteins like collagen lose their strength, cannot support |
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Mutation in non-coding DNA? |
Alter how genes are expressed |
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Types of Mutation |
•Insertions •Deletions •Substitutions |
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Insertions |
New base inserted into DNA base sequence where it shouldn't be
Change the way groups of three bases are 'read' Changes the Amino acids they code for
Have knock on effect as base is ADDED
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Deletions |
Random base is deletes from DNA base sequence
Change the way base sequence is read
Knock on effect as base is DELETED |
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Substitutions |
Random base in DNA base sequence is changed to a different base
NO knock on effect as base is REPLACED |
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Sexual Reproduction |
Produces Genetically Different Cells
Genetic info from two organism is combined to produce offspring which are genetically different to either parent
•Mother and father produce GAMETES by MEIOSIS
•Egg and sperm fuse together
•23 chromosomes from Father •23 chromosomes from Mother
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Asexual Reproduction |
Produces Genetically Identical Cells
Only one parent
Happens by MITOSIS
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Meiosis |
1) Cell duplicates genetic info, forming two armed chromosomes
2) FIRST DIVISION Pairs line up in centre of cell
3) Pairs then pulled apart so each new cell only has one copy of each chromosome - Some FC and MC IN each
4) SECOND DIVISON Cs line up again in centre Arms of CS pulled apart
4 GAMETES PRODUCED |
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Sexual Reproduction Advantages |
•Variation in Offspring - increases chance of species surviving a change in environment
•Individuals with characteristics better adapted to the enviro have a better chance of survival •More likely to breed successfully and pass those genes on
•Selective Breeding can be used to produce individuals with desirable characteristics •Increase food production by breeding animals that have a lot of meat
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Asexual Reproduction Advantages |
Only needs one parent - Less energy - Faster
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How many chromosomes in each cell? |
23 |
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23rd pair of chromosomes determine? |
Sex
XY- MALE XX- FEMALE AF |
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Non-coding GeneS |
Controls different characteristics |
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Allele |
Version of gene TWO for every gene |
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Homozygous |
Two same alleles |
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Heterozygous |
Two different alleles |
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Recessive |
lowercase
For organism to display recessive characteristics, both alleles must be recessive |
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Dominant |
UPPERCASE For organism to display dominant characteristic, only needs one dominant allele |
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Genotype |
Combination of alleles you have |
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Phenotype |
the characteristic which is expressed |
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Genetic Diagrams |
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Embryonic Screening |
•Analyse cell removed from embryo and check for genetic disorders •Analyse DNA from embryo in the womb
Embryos with 'bad alleles' produced by IVF are destroyed
Embryos in the womb, possible termination of pregnancy
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AGAINST Embryonic Screening |
Implies people with genetic problems are undesirable - increase prejudice May come a point where everyone wants to screen their embryos Expensive |
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FOR Embryonic Screening |
Will help stop people suffering Treating disorders cost Government and taxpayers lots of money - would not be an issue any longer There are laws to stop it going too far |
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Mendel |
Did genetic experiments with Pea Plants
•Tall pea plant X Dwarf pea plant •All Tall
•Two pea plant from 1st set •Three tall, one dwarf |
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Mendel's Conclusions |
•Characteristics in plants are determined by "hereditary units" •Units passed on to offsprings unchanged from both parents, one unit from each •Units can be dominant or recessive |
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Why did it take so long for Mendel's work to be understood? |
Didn't have the BG to properly understand his findings No idea about - Genes - DNA - Chromosomes |
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Variation |
Differences within a species Environmental and Genetic |
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Evolution |
The process of gradual change that takes place over many generations during which species of animals plants or insects slowly change some of the physical characteristics |
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Speciation |
ksnd |
