Biomed - Wk1 - Lectures 1,2,3

What is a disease?

An illness that affects the body (a single area or the whole system) and/or mind within a single organism.

What is biochemistry?

The chemistry of life; the study of the structures and interactions of biological molecules.

What does molecular biology study?

How the living cell carries out the necessary functions of life.

What does genetics study?

Heredity and the variation of inherited characteristics.

What is pharmacology?

The study of the body's reaction to drugs.

What does neuroscience study?

The structure and function of the nervous system and brain.

What is microbiology?

The study of microorganisms and their effects on other living organisms.

What are macromolecules?

Large molecules composed of thousands of covalently connected atoms.

Why are proteins important in defining cell characteristics?

The proteins expressed in a particular cell define its characteristics, leading to differences between cell types (e.g., liver vs. brain cells) and healthy vs. sick cells.

What determines a protein’s three-dimensional structure?

The sequence of amino acids.

What determines a protein’s function?

Its structure.

What is the significance of protein structure?

Proteins have a diversity of structures, resulting in a wide range of functions.

What are the four levels of protein structure?

1. Primary – Sequence of amino acids. 2. Secondary – Local folding into structures like alpha-helices and beta-sheets. 3. Tertiary – Overall 3D shape of a single polypeptide chain. 4. Quaternary – Arrangement of multiple polypeptide chains into a functional protein.

What are the most abundant biochemicals?

Sugars and the polymers of sugars.

What process produces carbohydrates?

Photosynthesis.

What are the simplest carbohydrates called?

Monosaccharides (single sugars).

Give three examples of monosaccharides.

Glucose, Fructose, Galactose.

What are disaccharides?

Carbohydrates made of two monosaccharides joined together.

Give two examples of disaccharides and their components.

Sucrose = Glucose + Fructose; Lactose = Glucose + Galactose.

What are polysaccharides?

Carbohydrate macromolecules composed of many sugar building blocks.

Give three examples of polysaccharides.

Muscle glycogen, starch, cellulose.

What must happen to lactose before it can be absorbed into the intestine?

It must be digested into its monosaccharide units (glucose and galactose).

What enzyme hydrolyzes lactose?

Lactase, found in the brush border of the GI tract.

What happens if lactase production is reduced?

The small intestine cannot digest lactose, leading to lactose intolerance.

What happens to unabsorbed lactose in lactose-intolerant individuals?

It is metabolized by intestinal bacteria, causing gas, cramping, and diarrhea.

What percentage of the world population is affected by primary lactose intolerance?

~70%.

What dairy products contain little lactose?

Cheese (especially hard cheeses) and yogurt.

How can lactose-intolerant individuals consume milk products?

By using milk treated with lactose-digesting enzymes.

What is galactosemia?

An inherited disorder where the body cannot metabolize galactose.

How common is galactosemia?

It occurs in 1 in every 60,000 births.

What enzyme is deficient in individuals with galactosemia?

Galactose-1-phosphate uridyltransferase (GALT).

What happens if an infant with galactosemia consumes milk?

Galactose-1-phosphate accumulates in the blood, leading to severe complications.

What are four major complications of galactosemia?

Liver damage, cognitive developmental delay, cataract formation, kidney failure.

What symptoms develop in a newborn with galactosemia after consuming milk for a few days?

Jaundice, vomiting, lethargy, irritability, and convulsions.

What are the four criteria that define a pandemic?

A new disease, occurs in humans, causes serious illness, passes easily from person to person.

What is antigenic variation?

A process where pathogens change their epitope expression to prevent recognition by the immune system.

Why must new flu vaccines be made each year?

The human influenza virus mutates rapidly, requiring updated vaccines to match new strains.

How can human viruses become more dangerous?

By exchanging genes with the viruses of domesticated animals, leading to new strains unrecognized by the human immune system.

Where are viruses found?

Viruses are found wherever there is life and may have existed since living cells first evolved.

What are virions?

Virus particles consisting of genetic material (DNA or RNA) surrounded by a protective protein coat.

What causes influenza (‘flu’)?

An RNA virus.

Why do new influenza strains replace older ones?

RNA viruses evolve rapidly, making previous vaccines ineffective.

How is influenza spread?

By coughing and sneezing.

What are some examples of autoimmune diseases?

Systemic lupus erythematosus, rheumatoid arthritis, insulin-dependent diabetes mellitus, and multiple sclerosis.

What happens in individuals with autoimmune diseases?

The immune system loses tolerance for self and attacks certain molecules of the body.

How does moderate exercise affect the immune system?

It improves immune system function.

What effect does psychological stress have on the immune system?

It disrupts immune system regulation by altering interactions between the hormonal, nervous, and immune systems.

Why is sufficient rest important for immunity?

It helps maintain proper immune system function.

How are gut health, nutrition, and the immune system related?

The gut microbiome and immune system are closely linked, with more than 70% of the immune system found in the gut.

What does the phrase “You are what you eat” refer to in the context of immunity?

It emphasizes the role of human nutrition and the gut microbiome in supporting immune system health.

What is the genome?

The genetic information unique to a given organism; the same genome is found in every cell of an individual.

What are genes?

The protein-coding regions of DNA; other regions are regulatory or have no known function.

How many chromosomes do human somatic cells have?

23 pairs (22 pairs of autosomes + 1 pair of sex chromosomes).

What is a karyotype?

An ordered display of an individual's chromosomes.

What are the three major classes of genetic disease?

Chromosomal disorders, Monogenic (single-gene) disorders, Polygenic (multi-gene) disorders.

What is aneuploidy?

A condition where an individual has an abnormal number of chromosomes due to nondisjunction during meiosis.

What causes Down syndrome?

Trisomy 21 – three copies of chromosome 21 due to nondisjunction.

What is Turner Syndrome?

A condition where a female has only one X chromosome (X0), leading to infertility.

What is Klinefelter Syndrome?

A condition in males where they inherit an extra X chromosome (XXY), affecting development.

How are monogenic disorders inherited?

They can be dominant (one mutated gene is enough) or recessive (two mutated copies needed).

Give examples of autosomal dominant disorders.

Huntington’s disease, Achondroplasia.

How are autosomal recessive disorders inherited?

Both parents must be carriers; the child has a 25% chance of being affected.

Give examples of autosomal recessive disorders.

Cystic fibrosis, Sickle cell anemia, Albinism.

What causes cystic fibrosis?

A mutation leading to defective chloride channels, causing mucus buildup.

What are symptoms of cystic fibrosis?

Thick, sticky mucus blocking bronchial tubes, difficulty absorbing nutrients in the small intestine, increased risk of infections and malnutrition.

How has treatment for cystic fibrosis improved?

Advances in therapy have significantly increased life expectancy and quality of life.

What are polygenic disorders?

Diseases caused by multiple genes and environmental factors.

Give examples of polygenic disorders.

Heart disease, diabetes, cancer, epilepsy, hypertension, manic depression, schizophrenia.

How heritable are polygenic disorders compared to monogenic disorders?

They have lower heritability (e.g., only 2-5% of close relatives of diabetics also have diabetes).