[BIO 1306] Ch17_Lecture

[BIO 1306] Ch17_Lecture - 17 Genome Sequencing, Molecular...

Info iconThis preview shows pages 1–14. Sign up to view the full content.

View Full Document Right Arrow Icon
17 Genome Sequencing, Molecular Biology, and Medicine
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
17 Genome Sequencing, Molecular Biology, and Medicine 17.1 How Do Defective Proteins Lead to Diseases? 17.2 What Kinds of DNA Changes Lead to Diseases? 17.3 How Does Genetic Screening Detect Diseases? 17.4 What Is Cancer? 17.5 How Are Genetic Diseases Treated? 17.6 What Have We Learned from the Human Genome Project?
Background image of page 2
17.1 How Do Defective Proteins Lead to Diseases? Genetic mutations are often expressed as proteins that differ from wild-type. Genetic diseases can result from abnormalities in enzymes, receptor proteins, transport proteins, structural proteins, etc.
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
17.1 How Do Defective Proteins Lead to Diseases? Phenylketonuria (PKU) was traced to its molecular phenotype in the 1950s. Results from an abnormal enzyme phenylalanine hydroxylase—normally catalyzes conversion of dietary phenylalanine to tyrosine. The abnormal enzyme has tryptophan instead of arginine in position 408.
Background image of page 4
Figure 17.1 One Gene, One Enzyme
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
17.1 How Do Defective Proteins Lead to Diseases? People with PKU have light skin and hair color. Melanin—pigment in dark skin and hair, is made from tyrosine, which people with PKU can not synthesize.
Background image of page 6
17.1 How Do Defective Proteins Lead to Diseases? Polymorphism in proteins does not always mean disease. There can be numerous normal alleles of a gene which produce normally functioning proteins.
Background image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
17.1 How Do Defective Proteins Lead to Diseases? The first human disease known to be caused by an abnormal protein was sickle-cell disease. The abnormal allele produces abnormal hemoglobin that results in sickle- shaped blood cells. The sickle-shaped cells block blood flow in capillaries.
Background image of page 8
17.1 How Do Defective Proteins Lead to Diseases? Hemoglobin—protein with quaternary structure; 2 α and 2 β chains. In sickle-cell disease, one of 146 amino acids in the β-globin chain is different: glutamic acid (negatively charged) is replaced by valine (neutral). Changes shape of the hemoglobin and causes anemia .
Background image of page 9

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
17.1How Do Defective Proteins Lead to Diseases? Variation in hemoglobin has been well documented. There are many amino acid substitutions; many have no effect on the protein function.
Background image of page 10
Figure 17.2 Hemoglobin Polymorphism
Background image of page 11

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
17.1 How Do Defective Proteins Lead to Diseases? Some diseases result from altered membrane receptors or transport proteins. Familial hypercholesterolemia (FH)— excess cholesterol can accumulate on artery walls and block them, causing heart attacks and strokes.
Background image of page 12
People with FH are unable to transport cholesterol to the liver and other cells that use it. Cholesterol travels as a lipoprotein (LDL). LDL binds to a receptor on a liver cell, and is taken up by endocytosis. In FH, the receptor protein is
Background image of page 13

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 14
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 129

[BIO 1306] Ch17_Lecture - 17 Genome Sequencing, Molecular...

This preview shows document pages 1 - 14. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online