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Mendel and Inheritance
Genotype: genetic makeup of an organism
allele
dominant alleles are descried using capital letter
Recessive alleles are represented by lower case
phenotype: the appearance of a trait in an organism
Heterozygous/ hybrid inheritance
having 2 alleles (dominant and recessive) for a trait for
homozygous/Pure inheritance
having the same alleles for a trait
Mendel and the pea
study inheritance traits
the pea was a good observant since it was readily available and reproduction was controllable
beginning of learning about inheritance traits
Dihybrid crosses - shows the possible offspring for 2 traits
mendelian ration 9:3:3:1
Monohybrid crosses - 1 trait crosses
complete dominance is 1 allele is always dominant over the other
the law of segregation - 1 allele from each parent code - For ex: Yy
incomplete dominance -neither alleles are dominant but are both expressed
produces a new phenotype
complete dominance - one allele is not completely dominant
(blending of the 2)
Meiosis: is the production of gamete cells
In the end 4 haploid daughter cells are produced
Meiosis 2: similar to mitosis (cell division)
telophase (II): nuclei forms and cytokenesis occurs
Anaphase (II): contracting to each poles
metaphase (II): Sister chromatids are splitting apart from metaphase plate (II)
Prophase (II) : preparing for the separation
Meiosis 1: will cross over genetic information between chromosome pairs + reduce chromosome number in half
Telophase 1
each pole now has a haploid set of chromosomes
Anaphase 1
homologue chromosomes split to each side of the poles
sister chromatids attach to the centromere
Metaphase 1
shortest phase where independent assortment occurs
genetic information is shared
tetrads align on the interphase plate
Prophase 1
synapsed the process of homologue chromosomes creating a tetrad
condensed
interphase (preparation of meiosis)
duplicate chromosomes with 2 identical sister chromatids
chromosomes replicated (s phase)
Non-Disjunction: happens when chromosomes do not divide precisely
Subtopic
KLEINFELTER’S SYNDROME
there is an extra X chromosome for a male
TURNER’S SYNDROME
one of the X chromosomes is missing or altered
DOWN’S SYNDROME
a genetic mutation caused by an extra partial or full chromosome on the 21st set
Reproductive strategies
Preimplantation genetic diagnosis
procedure used prior detect any genetic disorders before implantation
stem cells
are cells in our body that can specialize in different parts of our body
transgenic organisms
beneficial to our society in finding ways to prevent or to cure diseases
used to produce medical proteins or treatments
reproductive cloning
reproducing genetically identical organisms
therapeutic cloning
producing genetically identical cells to help treat diseases if needed
In vitro fertilization
used to fertilize an egg outside of the females body and egg combined in the laboratory with the sperm
Body cells and chromosomes
somatic cells
body cells
skin cells, brain cells etc
contain a normal amount of chromosomes (46)
diploid # = 2N
homologues
one homologue comes from the father and the other comes from the mother
Karyotype is the display of human chromosomes
homologue chromosomes
pair of chromosomes (maternal, paternal)
homologues pairs (Tetrads) carry genes controlling an inherited trait
each position of the gene is in the same position as a homologue
gamete cells
Sex cell including sperm and Ova (egg) cells
sperm located in testes
ova located in the ovaries
During ovulation ovum is released and transported to the fallopian tube
23+23=2N (46) a fertilize egg
contains 1/2 number of chromosomes = haploid (n)
DNA and RNA
Mutations
Possibility on not passing to the offspring but can be dangerous for coming generations
caused by: errors throughout cell division, replication, transcription and external agents
RNA (Ribonucleic acid)
single strand of nucleotides and it occurs in a variety of lengths and shapes.
MRNA : is a type of RNA leaves the nucleus (VIA endoplasmic reticulum) with the code of protein
Nucleotides sequencing transcribed from DNA to mRNA, this is a genetic message
Amino Acids is a type of protein
20 possible combinations of amino acids
production of proteins STOP and START codons
20AA act like the alphabet
64 different combinations
RNA contains a replacement nitrogenous base thymine for URACIL (U)
DNA (Deoxyribonucleic Acid)
DNA to protein
sequences of nucleotides in DNA contain information
are put to work through proteins
protein fold into 3D shapes and are key regulators
DNA replication
when two daughter cells duplicate, they must contain the same genetic information as a parent cell
DNA replicates its chromosomes through DNA replication
each cell has a copy of DNA that is present in the zygote
DNA structure
Codons are bases arranged in sequences of triplets
Coding can change the entirety of an organism
must be paired with the correct base bonds
phosphate group and pentose sugar form a backbone in DNA
Nucleotides such as phosphate group, pentose sugar and nitrogenous bases
Nitrogenous bases form rungs
Guanine and Cytosine
Adenine and thymine
arranged in a ladder like structure called double helix
final word in hereditary traits since it controls the structure of protein
depend on proteins called enzymes (ex: saliva)
Prenatal Testing
GENETIC COUNSELLING
Understand what the results of these tests will mean for you and your family
NUCHAL TRANSLUCENCY SCREENING
measures the fluid at the back of a baby’s neck
CHORIONIC VILLUS SAMPLING
doctor is removing a few cells from the developing placenta
AMNIOCENTESIS
women who are at risk should get this procedure done
if a fetus has a particular genetic disorder
Down syndrome, sickle cell disease, cystic fibrosis etc
