Human Genetics chapter10

Question 0

Substrate

Answer 0

Many proteins act as enzymes, they convert substrates, the specific chemical compound that is acted on by a an enzyme into products

Question 1

Mutations to proteins can do what?

Mutations to enzymes can do what?

Answer 1

1. Mutations altering a protein amino acid sequence can result in phenotypes ranging from insignificant to lethal
2. Mutations to enzymes can be especially damaging because
   A. Enzymes facilitate biochemical reactions by chemically converting substrates (molecules) to products

Question 2

Product

Answer 2

1. The specific chemical compound that is the result of enzymatic action. In biochemical pathways, a compound can serve as the product of one reaction and the substrate for the next reaction.

Question 3

Metabolic pathway

Answer 3

1. Interconnected enzymatic reactions that form chains of reactions

Question 4

Metabolism

Answer 4

The sum of all biochemical reactions going on in a cell, by which cells convert and utilize energy.

Question 5

Inborn error of metabolism

Answer 5

1. The concept advanced by Archibald Garrod that many genetic traits result from alterations in biochemical pathways.
2. Human genetic disorders and metabolism are related
3. These traits are inherited

Question 6

Mutations can?

Answer 6

1. Eliminate or alter the activity of an enzyme
2. Blocked reaction: a build up that reaches toxic levels from an accumulation of compounds resulting in abnormal phenotype
3. An essential enzyme required to produce a molecule needed for some cellular function is lost

Question 7

Essential amino acids

Answer 7

1. Amino acids (9) that cannot be synthesized in the body and must be supplied in the diet.

Question 8

Phenylketonuria

Answer 8

1. Results from a mutation that prevents conversion of phenylalanine to tryrosine
2. Affected people lack the enzyme PAH (involved in amino acid metabolism)
3. PKU affected individuals build up high levels of PHE and can result in mental retardation, neurological disorders
4. Usually have lighter skin and hair than their siblings
5. PKU can be treated with diet and supplements
6. Autosomal recessive
7. All children of a PKU woman who eat a regular diet during pregnancy will be mentally retarded

Question 9

Disorders can stem from?

Answer 9

1. Genes that affect lipid metabolism, Nucleic acid metabolism and carbohydrate metabolism
2. Mutations in receptor proteins

Question 10

Galactosemia

Answer 10

A heritable trait associated with the inability to metabolize the sugar galactose. If it is left untreated, high levels of galactose-1- phosphate accumulate, causing cataracts and mental retardation.

Question 11

Hemoglobin

Answer 11

1. An iron containing protein in red blood cells that transports oxygen from the lungs to the cells of the body
2. Millions of Adult hemoglobin (hba) molecules are produced each second of each day
3. Two copies of globin genes per chromosome

Question 12

Globins

Answer 12

1. Hemoglobin is composed of four protein molecules (adults hemoglobins are made of two alpha and two beta globins)
2. Each globin contains an iron containing heme group

Question 13

Pseudo genes

Answer 13

1. Non functional copies of genes (we have three) whose nucleotide sequence is similar to the functional gene, but mutations prevent their expression
2. Evolutionary defunct copies of versions we use now

Question 14

Hemoglobin variants

Answer 14

1. Hemoglobin disorder
2. Amino acid sequence changes in globins
3. Mutation in sickle cell anemia (hemoglobin disorder) showed that a single nucleotide change is sufficient to cause a genetic disorder
4. More than 400 variants identified, each caused by a different mutation
5. 90% caused by substitution of an amino acid, 60% of these in the beta globin chain

Question 15

Thalassemias

Answer 15

Imbalances of globin synthesis

Question 16

Sickle cell anemia

Answer 16

1. Autosomal recessive disorder
2. Caused by production of abnormal hba molecules that unload oxygen, and polymerize into rods
3. Rods elongate RBCs and form crescent or sickle shape
4. Anemia, cells are torn apart and don’t get replaced fast enough
5. Can lead to heart failure
6. Causes by mutation in beta globin gene, change in beta chain at chromosome 6

Question 17

Pharmacogenetics

Answer 17

A branch of genetics concerned with the identification of protein variants that underlie differences in the response to drugs.

Question 18

Ecogenetics

Answer 18

A branch of genetics that studies genetic traits related to the response to environmental substances.