2MARKS: PART 1

THE FUNCTIONS OF NUCLEUS:

  • It controls the heredity characteristics of an organism.
  • It is responsible for protein synthesis, cell division, growth and differentiation.
  • Stores heredity material in the form of deoxy-ribonucleic acid (DNA) strands.
  • Also stores proteins and ribonucleic acid (RNA) in the nucleolus.
  • It is a site for transcription process in which messenger RNA (m RNA) are produced for protein synthesis.
  • Aids in exchange of DNA and RNA (heredity materials) between the nucleus and the rest of the cell.
  • Nucleolus produces ribosomes and are known as protein factories.
  • It also regulates the integrity of genes and gene expression.

FUNCTIONS OF PLASMA MEMBRANE:

  • Plasma membrane separates the components of the cell from its outside environment.
  • It regulates what enters and exits the cell.
  • It allows only selected substances into the cell and keeps others out.
  • Plasma membrane has a major role in protecting the integrity of the interior of the cell.
  • Plasma membrane serves as a base of attachment for the cytoskeleton in some organisms and cell walls in other organisms. Thus it supports the cell and helps in maintaining the shape of the cell.
  • Plasma membrane is composed of lipids and proteins. Lipids give flexibility to membranes and proteins maintain the chemical climate of the cell and help in transfer of molecules across the membrane.
  • The lipid bi layer is semi permeable, that is, it allows selected molecules to diffuse across the membrane.

ENDOCYTOSIS:

Is the process by which materials move into the cell. There are three types of endocytosis: phagocytosis, pinocytosis, and receptor-mediated endocytosis. In phagocytosis or “cellular eating,” the cell’s plasma membrane surrounds a macromolecule or even an entire cell from the extracellular environment and buds off to form a food vacuole or phagosome.


EXOCYTOSIS:

In this process, the Golgi complex packages macromolecules into transport vesicles that travel to and fuse with the plasma membrane. This fusion causes the vesicle to spill its contents out of the cell. Exocytosis is important in expulsion of waste materials out of the cell and in the secretion of cellular products such as digestive enzymes or hormones.


ACTIVE TRANSPORT:

  • Active transport moves ions or molecules in a specific direction through the use of an integral membrane protein.
  • There are three types of membrane proteins that use energy to push these substances against the concentration gradient.
  • A uniport is an integral membrane protein that moves an ion or molecule in one direction. ‘Uni’ can remind you of the word ‘one,’ such as one substance moving in one direction
  • An antiport is an integral membrane protein that moves one ion or molecule in one direction while moving a second substance in an opposite direction. The ‘anti’ in antiport means ‘against.
  • A symport is an integral membrane protein that moves two ions or molecules in the same direction. ‘Sym’ in symport stands for the word ‘same,’ as in two substances moving in the same direction.

PASSIVE TRANSPORT:

A kind of transport by which ions or molecules move along a concentration gradient, which means movement from an area of higher concentration to an area of lower concentration.

There are four major types of passive transport:

  • Simple Diffusion
  • Facilitated Diffusion
  • Filtration
  • Osmosis.

MUTAROTATION :

A process that produces a change in op­tical rotation of a solution of two or more equilibrating species from the optical rotation of a pure substance to that of the equilibrium mixture; a change in optical rotation that takes place when a pure sugar anomer is dissolved.


EPIMERS:

Epimers are diastereomers that contain more than one chiral center but differ from each other in the absolute configuration at only one chiral center.


ENANTIOMERS:

An enantiomer is one of the two molecules that are mirror images of each other and are non-superposable. Enantiomers have identical chemical and physical properties except for their ability to rotate plane-polarized light (+/-) by equal amounts but in opposite directions. Enantiomers interact differently with other chiral molecules.


OPTICAL ISOMERISM:

Optical isomers are named like this because of their effect on plane polarized light. Optical isomerism is a form of stereoisomerism.


BENEDICT’S REACTION:

Benedict’s Test is used to test for simple carbohydrates. The Benedict’s test identifies reducing sugars , which have free ketone or aldehyde functional groups. Benedict’s solution can be used to test for the presence of glucose in urine.

Procedure of Benedict’s Test

  1. Approximately 1 ml of sample is placed into a clean test tube.
  2. 2 ml (10 drops) of Benedict’s reagent (CuSO4) is placed in the test tube.
  3. The solution is then heated in a boiling water bath for 3-5 minutes.
  4. Observe for color change in the solution of test tubes or precipitate formation.

Positive Benedict’s Test: Formation of a reddish precipitate within three minutes. Reducing sugars present. Example: Glucose
Negative Benedict’s Test: No color change (Remains Blue). Reducing sugars absent. Example: Sucrose.


RENATURATION:

ANSWER 1:

The process by which proteins or complementary strands of nucleic acids re-form their native conformations.

ANSWER 2:

Renaturation in molecular biology refers to the reconstruction of a protein or nucleic acid (such as DNA) to their original form especially after denaturation. This process is therefore the inverse of denaturation. In denaturation, the proteins or nucleic acids lose their native bimolecular structure.


COAGULATION:

The process by which the blood clots to form solid masses, or clots. Platelets produce a substance that combines with calcium ions in the blood to form thromboplastin, which in turn converts the protein prothrombin into thrombin in a complex series of reactions.


PROTEOLYTIC ENZYMES OF PANCREAS:

Pancreatic enzymes help break down fats, proteins and carbohydrates. A normally functioning pancreas secretes about 8 cups of pancreatic juice into the duodenum, daily. This fluid contains pancreatic enzymes to help with digestion and bicarbonate to neutralize stomach acid as it enters the small intestine.

Types of Pancreatic Enzymes and Their Effects:

Effects:
Lipase works with bile from the liver to break down fat molecules so they can be absorbed and used by the body.

Shortage may cause:

  • Lack of needed fats and fat-soluble vitamins.
  • Diarrhea and/or fatty stools.

Protease

Effects:
Proteases break down proteins. They help keep the intestine free of parasites such as bacteria, yeast and protozoa.

Shortage may cause:

  • Allergies or the formation of toxic substances due to incomplete digestion of proteins.
  • Increased risk for intestinal infections.

Amylase

Effects:
Amylase breaks down carbohydrates (starch) into sugars which are more easily absorbed by the body. This enzyme is also found in saliva.

Shortage may cause:

  • Diarrhea due to the effects of undigested starch in the colon.

THE HORMONES WHICH STIMULATE PANCREATIC SECRETION:

The exocrine pancreas secretes digestive enzymes, fluid, and bicarbonate in response to food ingestion. This is a critical digestive process that is regulated by neural reflexes, gastrointestinal hormones, and absorbed nutrients. In the absence of proper pancreatic secretion, maldigestion and malabsorption of nutrients may cause malnutrition and associated complications.


TRYPSINOGEN:

Trypsinogen is a substance that is normally produced in the pancreas and released into the small intestine. Trypsinogen is converted to trypsin. Then it starts the process needed to break down proteins into their building blocks (called amino acids).


CATHERINE SHALINI RAJA
M.P.T.,MIAP.,PGDYN
CARDIO RESPIRATORY PHYSCIAL THERAPIST
FITNESS & SPORTS REHABILITATION SPECIALIST

One Reply to “2MARKS: PART 1”

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.