The Role of Genes in Heredity.pptx

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1. T h e 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.

4. The Role of Genes in Heredity

5. 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.

6. 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.

7. 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 .

8. 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.

9. 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.

10. 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,

11. 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.

12. 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.

13. 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 .

14. 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

15. 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 help to stop bleeding.

16. Effect of Genes in Our Environment

17. 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:

18. 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.

19. 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.

20. Gene Mutations

21. 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.

22. 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.

23. 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.

24. 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.

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

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

27. 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).

28. 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.

29. DNA Code

30. 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.

31. 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.

32. 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.

33. 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.

34. The Genetic Code

35. 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.

36. 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.

37. 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.