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Unit 11-Learning Aim C (DISTINCTION)
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This is learning aim C for unit 11-genetics and genetic engineering, in which I got a DISTINCTION by hitting all the criteria presented.
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Unit 11 Aim C: Genetics and Genetic Variation:In 1886 a man known as Gregor Mendel decided to publish the results of investigations he had
been doing into cross breeding pea plants and he also made these results public to the science
community as a whole; despite the fact he had no knowledge about chromosomes and meiosis
he still managed to prove that the units of inheritance were real, he did this by predicting the
formation of gametes and sperm during their formation, from his own accurate and
quantitative data, as he worked with 7 different traits and characteristics that were shown by
the pea plant, these were, stem height, pod colour, seed colour, shape, arrangement, seed
shape, and flower colour; he derived two laws which are known as Mendel’s laws, these laws
are, the law of segregation and the law of independent assortment, the law of segregation is: in
each diploid parent cell, every gene has two alleles, and at meiosis each gamete receives only
one allele of the gene as the chromosomes halved, which means that only one allele of each
gene is received, whilst the law of independent assortment is when the chromosomes of each
homologous pair are arranged randomly in meiosis 1 and this happens randomly according to
how the chromosomes are lined up on the equator of the spindle in meiosis 1; in meiosis 2
chromatids are also arranged independently based on the way they are lined up on the equator
of the spindle at metaphase 2 which is then pulled apart by anaphase 2, this results in the
independent assortment of members of different pairs of alleles, into the resulting gametes;
after this the pairing of male and female gametes is random, therefore any pair of alleles for a
gene in a female gamete can now combine with any pair of alleles for the same gene in the
male gamete.
Gene:
Genes are inherited instructions that consist of DNA (deoxyribonucleic acid), these genes
control several structures and functions.
Allele:
Alleles are a different form of genes, alleles come about due to mutation, however they are not
necessarily harmful.
Genotype:
Genotypes are the genetic constituents of an organism; they can also be the genetic make-up of
an organism/ group of organisms that references a single trait or set of traits.
Phenotype:
Phenotypes refer to the visible traits and characteristics an organism has.
Gene locus:
A gene locus refers to the position a gene is in when on a chromosome.
,Dominant & Recessive
This is the allele that has visible expressions whether there are only one or more alleles of the
gene present. Whereas recessive refers to alleles that do not have visible expressions if the
dominant allele of the gene is present.
Heterozygous & Homozygous
Heterozygous is when an organism has two completely different alleles for the same gene.
However, homozygous is when both alleles for an organism are identical.
Complete Dominance:
This is when the phenotype of heterozygous individuals are the same as the homozygous
dominant individuals, this is known as complete dominance.
Incomplete Dominance:
This is when both the alleles are expressed from each other; and It occurs when the children of
parents with diametrically opposed personality traits show intermediate phenotypes. For
instance, if red-flowering elephant plants and white-flowering elephant plants are crossed,
every offspring will have an equal blend of both colours, creating a pink coloration. By crossing
the potential first filial generation members, this crossing can be predicted. An example is:
Co dominance:
This refers to intermediate phenotypes that are observed, and it occurs when a heterozygote
expresses both alleles of a gene locus. Both alleles are expressed in the indicated recessive
situations at the molecular level. Nevertheless, this is because heterozygous carriers only have
one normal allele of the gene. They manufacture enough protein to effectively treat the
disease's symptoms. Even when both alleles are expressed, they do not influence the
phenotypic features, thus heterozygous individuals do not exhibit illness symptoms. They might
only have half as much of the protein in question as is typical. People with TaySachs or potential
cystic fibrosis carriers may benefit from this because they may be less vulnerable to
tuberculosis, which is a leading cause of mortality for Tay Sachs patients. Blood types are an
illustration of co-dominance, wherein the phenotype of a heterozygous individual is influenced
by both alleles. A single gene on chromosome 9 has three alleles that determine all 4 blood
types. Even though there are three alleles of this gene in the gene pool, each person can only
have two of these three alleles present in their genome.
, The Y-linked inheritance method can be used to pass along genes present on the Y
chromosome. The sex chromosomes of male mammals, including humans, are the X and Y
chromosomes. Due to its smaller size, the Y chromosome has fewer genes than the X
chromosome. In addition to the genes required for healthy hormone production, sperm
development, and other traits specific to males, the Y chromosome also contains genes that are
not involved in sex determination. Some examples of Y-linked inheritance include porcupine
man, webbed toes, and hypertrichosis of the ears are a few examples of Y-linked inheritance in
people. A visible hair development on the outer rim of the ear is a defining feature of the
condition known as hypertrichosis of the ears, also referred to as hairy ears. The disorder
known as "webbed toes" is distinguished by a web-like connection between the second and
third toes. The disorder is referred to as "porcupine man" as the skin thickens and gradually
darkens, scalds, becomes rough, and sprouts bristle-like growths. Given that the Y chromosome
is involved, Y-linked inheritance is passed down from father to son. Uncontrollable hair growth
on the body and face is a symptom of the medical condition hypertrichosis; Y-linked
hypertrichosis is caused by a change in the Y chromosome that affects how hair development is
controlled. The precise gene that causes this condition is yet unclear, but there may be other
genetic and environmental variables that influence how it manifests. Due to the way it is
inherited, the rare genetic disorder Y-linked hypertrichosis can only be passed from fathers to
their sons. Because the Y chromosome only exists in males, Y-linked traits cannot be passed
down to females. Because of this, neither females nor males without a Y chromosome can
suffer Y-linked hypertrichosis. Y-linked hypertrichosis is caused by a change in the Y
chromosome that affects how hair development is controlled. This sickness may also be
influenced by environmental variables and unidentified genes, and there may be more genetic
components as well. In addition to having more body hair than the normal person, people with
Y-linked hypertrichosis may also have hair that grows in unusual areas, such as their ears, nose,
and forehead. Because of how apparent the condition is, even though it is typically not harmful,
it can cause social and psychological problems. Although there is no known cure for
hypertrichosis, hair removal methods including shaving, waxing, and laser hair removal can help
manage the symptoms. This is a pedigree chart for this inherited illness:
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