Life Sciences 2 - Exam - Short Answer Questions - Part 2 Flashcards
What are the 5 Determinants of Health?
- Biomedical factors: hypertension, high cholesterol levels, asthma arthritis.
- Lifestyle and behaviour factors: tobacco smoking, diet and nutrition, alcohol consumption.
- Knowledge, attitudes and beliefs: influence on our lifestyle, behaviour, hence our health
- Genetic factors – genetic disorders.
- Environmental factors – political social and physical environmental factors.
What is gram staining? What colour are gram - negative bacteria? what colour are gram - positive bacteria?
Gram staining is a procedure to classify bacteria by the ability of the cell wall to absorb a crystal violet dye followed by a red safranin counter stain.
Gram negative bacteria is Pink or red. Because they do not retain the crystal violet dye.
Gram positive bacteria are Blue or purple.
What is DALY? What contributes to DALY?
What is YLDs?
What is YLL?
DALY: Disability-Adjusted Life Years (DALY) is a measure of the overall disease burden, representing the total number of years lost due to illness, disability, or premature death. It is calculated by adding Years of Life Lost (YLL) due to premature mortality and Years Lived with Disability (YLD) due to illness.
DALY = YLL + YLD
YLDs: YLDs = Years lived with disability.
YLL: Years of Life Lost due to disability.
How does a vaccine help the immune system to recognize and respond to pathogens?
Vaccines introduce a weakened or inactivated form of a pathogen, or parts of it, to the immune system. This exposure stimulates the production of antibodies without causing illness, allowing the immune system to “remember” the pathogen and respond more effectively if exposed to it again.
What distinguishes viruses from other microorganisms like bacteria and fungi?
Viruses are unique in that they require a host cell to replicate, as they lack cellular structures like organelles and cannot perform metabolism on their own. Bacteria, in contrast, are single-celled organisms with cell walls and can often survive independently.
How do parasitic organisms differ in structure and function from bacterial organisms?
Parasites are organisms that live on or inside a host and rely on the host for sustenance, often harming the host in the process. Unlike bacteria, which can survive independently, parasites are usually more complex and may have specialized adaptations for living within or on a host organism.
Describe how the body breaks down lipids for absorption in the digestive system.
Lipids are broken down in the digestive system through a process called emulsification, where bile salts produced by the liver help to disperse fats into smaller droplets. Lipase enzymes then break down these fats into fatty acids and glycerol, which can be absorbed by the intestines.
What role do bile salts play in the digestion and absorption of lipids?
Bile salts emulsify fats in the small intestine, breaking them into tiny droplets that increase the surface area for the enzyme lipase to act. This process aids in the digestion and absorption of lipids, allowing them to be used as a source of energy in the body.
How did the acceptance of the germ theory of disease replace the spontaneous generation theory?
The germ theory of disease, which proposes that diseases are caused by specific microorganisms, replaced the spontaneous generation theory, which claimed that life could arise spontaneously from non-living matter. Experiments by scientists like Louis Pasteur demonstrated that microorganisms cause disease, supporting the germ theory.
What are two key structural differences between bacterial cells and human cells?
Bacterial cells lack a nucleus and other membrane-bound organelles found in human cells. Additionally, bacterial cells have a cell wall composed of peptidoglycan, while human cells do not have a cell wall.
Describe the basic structure of a protein and its primary function in the body.
Proteins are composed of long chains of amino acids that fold into specific shapes, which determine their function. Proteins serve as enzymes, structural components, and signalling molecules in the body, among other functions.
Describe one step in the digestion of carbohydrates in the human body.
Carbohydrate digestion begins in the mouth, where the enzyme amylase in saliva breaks down starches into simpler sugars, such as maltose.
How do antiviral medications differ from antibiotics in terms of their action on pathogens?
Antiviral medications inhibit the replication of viruses by targeting specific stages of their life cycle, whereas antibiotics target bacterial cell structures or functions, such as cell wall synthesis, which are not found in viruses.
What structural feature allows fungi to thrive in a variety of environmental conditions?
Fungi have a tough cell wall made of chitin, which allows them to survive in various environmental conditions and helps protect them from desiccation and other environmental stresses.
How do bacterial spores contribute to bacterial survival in harsh conditions?
Bacterial spores are a dormant, tough, and non-reproductive form of the cell that can survive in extreme conditions like heat, drought, and exposure to chemicals, allowing bacteria to persist until conditions are favourable for growth.
