gene

1. The Role of
Genes
in Heredity

2. Agree or Disagree: Discuss the topics below according
to your opinion. Group yourselves based on your
opinions (if you agree or disagree). Within your group,
prepare pointers for your discussion.
TOPIC:
a. use of genetically modified milk from
animals for human consumption.
b. economic concerns moral issues of
genetic modification of food and food
products.

3. HEREDITY- is the passing on of traits from
parents to their offspring, either through asexual
reproduction or sexual reproduction, the
offspring cells or organisms acquire the genetic
information of their parents, through heredity,
variations between individuals can accumulate
and cause species to evoke by natural
selection. The study of heredity is a biology of
genetics.

6.  The heredity information is contained within
the genes, located in the chromosomes of
each cell. An inherited trait can be determined
by one or by many genes and a single gene
can influence more than one trait. A human
cell contains many thousands of different
genes in the nucleus.

7.  Heredity factors known as genes are thought
to exist as discrete portions (known as loci) of
chromosomes. The term “discrete” refers to
the concept that genes are always located at
the same point or (locus) on a chromosome.

9.  It is believed that pairs of homologous
chromosomes contain linear, matching
arrangements of genes exerting parallel
control over the same traits. Pairs of genes
that exercise such parallel control over the
same traits are known as alleles of two kinds:
dominant and recessive.

10. An allele is a variant form of a gene. Some genes have various
forms, located at the same position, or genetic locus, on a
chromosome. Humans are called diploid organisms because
they have two alleles at each genetic locus, with one allele
inherited from each parent. Each pair of alleles represents the
genotype of a specific gene. Genotypes are described as
homozygous if there are two identical alleles at a particular locus
and as heterozygous if the two alleles differ. Alleles contribute to
the organism's phenotype, which is the outward appearance of
the organism.

11.  Genetics characteristics can be extremely
complex and may require the actions of
several separate genes to be expressed in the
adult organism. An example of traits that
require more than a single pair of genes to be
expressed are human height and human
color.

12.  Other traits may be controlled by a single pair
of genes. Some of these traits may have
extreme phenotypes, such as albinism (lack of
skin pigment) in humans,

13. Albinism is an inherited condition that leads to someone having
very light skin, hair, and eyes. It happens because they have
less melanin than usual in their body. Melanin gives skin, hair,
and eyes their color. Except for vision problems, most people
with albinism are just as healthy as anyone else.

14. Common genetic disorder
Down syndrome
Down syndrome is also
referred to as Trisomy 21. This
extra copy changes how the
baby's body and brain develop,
which can cause both mental
and physical challenges for the
baby. Even though people with
Down syndrome might act and
look similar, each person has
different abilities.

15. Common genetic disorder
Sickle cell disease
Sickle cell disease is a
group of inherited red
blood cell disorders that
affect hemoglobin, the
protein that carries
oxygen through the
body.

16. Common genetic disorder
Phenyl ketoneeria (PKL)
Phenylketonuria (commonly
known as PKU) is an inherited
disorder that increases the
levels of a substance called
phenylalanine in the blood.
Phenylalanine is a protein
building block (an amino acid )
that is obtained from eating
certain foods (such as meat,
eggs, nuts, and milk) and in
some artificial

17. Common genetic disorder
hemophilia
Hemophilia is usually an
inherited bleeding
disorder in which the
blood does not clot
properly. This can lead
to spontaneous bleeding
as well as bleeding
following injuries or
surgery. Blood contains
many proteins called
clotting factors that can

19.  Genes are inherited, but their expression can
be modified by interactions with the
environment. Genetic traits are determined
largely through the precise information found
in the cell’s gene structure. A variety of
factors in the environment can actually alter
the effects of a particular gene. Some
examples of this effect are as follows:

20.  Effect of light or chlorophyll production –
although most plants have the genetic ability to
produce chlorophyll, they will do this only in the
presence of light. Without light, these plants
produce only a light-yellow pigment and therefore
appear pale and sickly until they are exposed to
sunlight. After a few days of exposure to sunlight,
the chlorophyll production mechanism is enabled
and the green color returns.

21. Cell store and use coded information. The genetic
information stored in DNA is used to direct the synthesis
of the thousands of proteins that each cell requires. The
cell contains many thousands of such codes in its
chromosomes. Each strand of DNA in the chromosome
has the potential to provide the complete chemical code
for the manufacture of at least one complete protein.
These proteins are highly specific and they result in the
expression of some specific trait or portion of a trait in the
living cell and, consequently, in the organism of which
they are part.

23.  Gene mutations may be defined as any changes in
the nitrogenous base sequence of a molecule
DNA. When the base sequence of DNA is altered,
the amino acid sequence of the polypeptide for
which it codes will likewise be altered. Such an
alteration may affect the operation of the resulting
enzyme, preventing it from property catalyzing its
reaction and thus preventing a trait from being
expressed by the cell.

24.  The majority of gene mutations are harmful
because they result in the cell being impaired from
performing some specific task. In rare cases, a
mutation may result in a lethal gene that kills the
cell either by producing a substance toxic to the
cell or by failing to produce a protein of vital
importance to the cell.

25.  The majority of gene mutations are harmful
because they result in the cell being impaired from
performing some specific task. In rare cases, a
mutation may result in a lethal gene that kills the
cell either by producing a substance toxic to the
cell or by failing to produce a protein of vital
importance to the cell.

26. On the other hand, DNA is a
polymer made up of a
repeating chemical unit known
as the NUCLEOTIDE.
Thousand of the units are
known to comprise a single-
DNA molecule, making it one
of the largest of all organic
compounds.

28. • Phosphate group
a chemical
group made up
of phosphorous
and oxygen.
 DNA nucleotides themselves are quite complex,
being composed of three separate subunits:

29. • Deoxyribose
a five-carbon
sugar made up
of carbon,
oxygen, and
hydrogen.
 DNA nucleotides themselves are quite complex,
being composed of three separate subunits:

30. • Nitrogenous base
A chemical unit
composed of
carbon, oxygen,
hydrogen, and
nitrogen.
 DNA nucleotides themselves are quite complex, being composed of
three separate subunits:
 Based found in DNA are Adenine (A), thymine (T), cytosine
(C), and guanine (G).

31.  Decoding messages is also a keep step in gene
expression, in which information from a gene is
read out to build a protein. Genetic code allows
DNA & RNA sequences to be “decoded” into amino
acids of a protein.

33.  The chemical and structural properties of DNA are
the bases for how the genetic information that
underlies heredity is encoded in genes (as a string of
molecular bases) and replicated by means of a
template. As we recall DNA is a complex organic
molecule composed of thousands of repeating
nucleotide molecules and each free nucleotide
carries with it one of our nitrogenous bases.

34.  The particular sequence of the nitrogenous bases
adenine, thymine, cytosine, and guanine (A, T, C,
and G) comprises a strand of DNA and provide the
type of chemical code that is understood by the
chemical mechanisms of the cell.

35.  The DNA code is used by these mechanisms to
manufacture specific enzymes and other proteins
through the process of protein synthesis.
 A DNA strand provides a template (pattern) for the
information of messenger RNA (mRNA). The DNA
code is transcribed (read) by mRNA as the latter is
synthesized in a pattern complementary to the
DNA strand.

36.  The process by which the DNA code is transferred
to mRNA code is known as transcription. In ENA
molecules, uracil (U) nucleotides are substituted for
DNA’s thymine (T).
 Each group of the three nitrogenous bases, known as a
triplet codon, provides the information necessary to code
for the insertion of a single, specific amino acid into
building protein molecule. The particular sequence of
triplet codons on DNA ( and transcribe to mRNA) enables
amino acids to be linked together in a specific sequence
during protein synthesis.

38.  Every organism requires a set of coded instructions
for specifying its traits. For offspring to resemble
their parents, information must be reliably
transferred from one generation to the next.
 Heredity is the passage of these instructions form
generation to another.
 Discoveries in genetic science, deoxyribonucleic
acid (DNA) was revealed to be the chemically
active agent of the gene. DNA replicates itself
when chromosomes replicate in the early stages of
cell division.

39.  DNA is passed from generation to generation
during reproduction and acts as genetic factor.
 DNA interacts with the cell’s chemical factor and
produces the observable effects of the phenotype
when genes are inherited by a cell or an organism.
 DNA regulates the production of enzymes in the
cell and thereby enables the cell to perform the
complex cellular chemical reactions necessary to
sustain life.

40.  Stem-cell therapy focuses on the use of stem cells
to treat or prevent a disease or condition. Stem
cells are a special read of cells that are capable of
differentiating into more than one kind of tissue.
 Stem cells are used for curing various diseases
such as diabetes, arthritis, a few cancers, and bone
marrow failure.
 Genetic engineering is a technique of controlled
manipulation of genes to change the genetic
makeup of cells and more genes across species
boundaries.