BIO503 Final Term Current Solved Papers by Bell

BIO503 ( Biophysics ) · Current File ( Final Term - 2022 ) · Write down the function of cell membrane. 5 Marks · Functions of the cell membrane:

• To maintain the physical integrity of the cell that is to mechanically enclose the contents of the cell, and also to control the movement of particles e.g., ions of molecules, into and out of the cell.
• The cell membrane maintains the physical integrity of the cell.
• It's most obvious in the cases of animal cells (because they don't have cell walls) that the cell membrane holds the cell together by enclosing the cytoplasm and organelles within it.
• The cell membrane forms a barrier between the inside of the cell and the environment outside the cell enclosing cytoplasm and any organelles within the cell and enabling different chemical environments to exist on each side of the cell membrane.
• The cell membrane physically separates the intracellular components (e.g., organelles in eukaryotic cells) from the extracellular environment.
• The cell membrane protects the cell from some harmful chemicals in its external environment.
• It also protects the cell from loss of useful biological macromolecules held within the cell by its plasma membrane.

What is active and passive electrolocation? 5 Marks

Active electrolocation:

In active electrolocation, the animal senses its surrounding environment by generating electric fields and detecting distortions in these fields using electroreceptor organs. This electric field is generated by means of a specialized electric organ consisting of modified muscle or nerves. This field may be modulated So that its frequency and wave form are unique to the species and sometimes, the individual.

Passive electrolocation:

In passive electrolocation, the animal senses the weak bioelectric fields generated by other animals and uses it to locate them. These electric fields are generated by all animals due to the activity of their nerves and muscles. A second source of electric fields in fish is the ion pumps associated with osmoregulation at the gill membrane. This field is modulated by the opening and closing of the mouth and gill slits. Many fish that prey on electrogenic fish use the discharges of their prey to detect them. This has driven the prey to evolve more complex or higher frequency signals that are harder to detect. What is electrolocation? 3 Marks

Electrolocation:

Electro-receptive animals use this sense to locate objects around them. This is important in ecological niches where the animal cannot depend on vision: for example, in caves, in murky water and at night. Many fish use electric fields to detect buried prey. Some shark embryos and pups "freeze" when they detect the characteristic electric signal of their predators.

Name of any four Amino acid?

• Histidine
• Isoleucine
• Leucine
• Lysine
• Methionine
• Phenylalanine
• Threonine
• Tryptophan
• Valine

What is Microsievert and millisievert?

Microsievert (MSV) is one millionth of a sievert (1/1,000000)

Millisievert (mSv) is one thousandth of a sievert (l/l ,000)

What is Saxitoxin?

Saxitoxin is a potent neurotoxin and the best-known paralytic shellfish toxin. Ingestion of saxitoxin by humans, usually by consumption of shellfish contaminated by toxic algal blooms, is responsible for the illness known as paralytic shellfish poisoning.

Name phases of matter?

• Solid
• Liquid
• Gas

Name the groups of lon channel? 3 Marks

• Ligand gated channels (neurotransmitters)
• Voltage gated channels trans-membrane potential (electric field)
• Second messenger gated channels nucleotides, (G-proteins)
• Mechano-sensitive channels osmotic pressure (membrane curvature)
• Gap junctions, (porins not gated)

What is Spectroscopy?

Spectroscopy is the study of the interaction between matter and electromagnetic radiation. Spectroscopy relates to the dispersion of an object's light into its component colours (i.e. Energies). Spectroscopy and spectrography are terms used to refer to the measurement of radiation intensity as a function of wavelength and are often used to describe experimental spectroscopic methods.

State two types of self-assembly? 2 Marks

There are two types of self-assembly. These are

1. Intra-molecular self-assembly
2. Intermolecular self-assembly

State fluid mosaic model? 2 Marks

The fluid mosaic model describes the structure of the plasma membrane as a mosaic of components including phospholipids, cholesterol, proteins and carbohydrates that gives the membrane a fluid character.

What is Radiation Protection? 2 Marks

Radiation protection, sometimes known as radiological protection, is defined by the International Atomic Energy Agency (IAEA) as " The protection of people from harmful effects of exposure to ionizing radiation, and the means for achieving this".

Who discovered DNA? And name of scientist discovered the structure of DNA?

2 Marks

In 1953 Watson and Crick determined the structure of DNA.

Define HPLC?

High-performance liquid chromatography (HIPLC) formerly referred to as high-pressure liquid chromatography is a technique in analytical chemistry used to separate, identify, and quantify each component in a mixture. High performance liquid chromatography is powerful tool in analysis, it yields high performance and high speed compared to traditional columns chromatography. HPLC is a chromatographic technique that can separate a mixture of compounds.

Define MRI (Magnetic Resonance Imaging)?

A medical imaging technique which is used in radiology to form images of the anatomy and the physiological processes of the body in both health and disease.

Define Electrophoresis?

Electrophoresis separates mixtures of proteins based on charge, charge/mass ratio or size.