overview Flashcards
What is Magnification?
The extent to which the image appears larger compared to the actual object.
How do you calculate magnification?
Magnification = Image size / Actual (real) size.
Define resolution in microscopy
The ability to distinguish two close points as separate; determines the image’s clarity and detail.
What is the field of view?
The visible area under the microscope.
What is the depth of field?
The extent to which the sample remains in focus at different depths.
What is an artefact in microscopy?
A structure that is not part of the specimen, often caused by processing techniques, such as drying out tissue with solvents like acetone.
What is fixation in electron microscopy?
Coating the specimen in heavy metals to prevent electrons from passing through, allowing for imaging.
What does staining do in microscopy?
Injects a resin into the specimen to preserve structures and enhance visibility.
Differentiate between light microscopes and electron microscopes
Light microscopes use visible light to view specimens, while electron microscopes use beams of electrons for higher resolution imaging.
What is the main function of the condenser lens in a light microscope?
It focuses light onto the specimen for better clarity
What are the two main types of sugars in carbohydrates?
Monosaccharides and disaccharides
Define a solute
A substance that dissolves in a solvent.
What is the primary structure of a protein?
The linear sequence of amino acids in a polypeptide chain.
Explain the term “hydrophobic”
Substances that repel water and do not mix well with it; they are non-polar.
What is a triglyceride?
A lipid made up of one glycerol and three fatty acids; commonly found in fats and oils.
What is the role of cholesterol in cell membranes?
It helps maintain fluidity and stability of the membrane by preventing fatty acid tails from packing too closely together.
Define denaturation in the context of enzymes
The disruption of the weak bonds maintaining an enzyme’s specific shape, leading to a loss of function.
describe the function of mRNA in protein synthesis
mRNA carries genetic information from DNA to the ribosome for protein synthesis.
What is the induced fit model of enzyme activity
A model suggesting that when a substrate binds to an enzyme, the enzyme undergoes a slight change in shape to better fit the substrate.
What is the genetic code?
The set of rules by which information encoded in genetic material is translated into proteins, comprising codons that specify amino acids.
What is dehydration in the context of microscopy?
Dehydration preserves structures by making cross-links in the tissue using chemicals like glutaraldehyde and osmium tetroxide.
How does embedding in resin enhance microscopy?
Embedding in resin increases contrast and improves visibility, allowing more detail to be seen.
Describe the function of the denser in a light microscope
The condenser focuses light from the light source onto the specimen for better clarity.
What is the role of the diaphragm/iris in microscopy?
The diaphragm controls the amount of light that passes through the specimen, affecting contrast and brightness.
What is the difference between coarse and fine focus knobs?
The coarse focus knob brings the specimen into general focus, while the fine focus knob adjusts the focus precisely at higher magnifications.
What is the total magnification of a microscope?
Total magnification = Objective lens magnification x Eyepiece lens magnification.
Define an atom
An atom is the smallest particle of an element.
What is a molecule?
A molecule is formed when two or more atoms are chemically bonded together.
Distinguish between solute and solvent
A solute is the substance that dissolves in a solvent, while a solvent is the substance that dissolves the solute.
What is a hydrogen bond?
A hydrogen bond is a weak interaction that occurs whenever molecules contain an electronegative atom bonded to a positively charged hydrogen atom.
List of key properties of water
Water is a universal solvent, has lower density when frozen, high specific heat capacity, cohesion and surface tension.
What are monosaccharides?
Monosaccharides are the simplest sugars, with a general formula of CnH2nOn.
What is the process of hydrolysis?
Hydrolysis is a catabolic reaction where water is used to break down larger molecules by splitting covalent bonds.
Define condensation reaction
A condensation reaction is an anabolic process where two smaller molecules combine to form a larger molecule, producing water in the process.
What is glycogen?
Glycogen is a stored form of glucose found primarily in the liver and muscles, serving as an energy reserve.
Explain the role of glucagon
Glucagon is a hormone produced by the pancreas that raises blood glucose levels by signaling the liver to break down glycogen into glucose.
define hydrophobic substances
Hydrophobic substances repel water and do not mix or dissolve in it because they are non-polar.
What are triglycerides?
Triglycerides are the most common lipids in the body, made up of one glycerol and three fatty acids.
distinguish between saturated and unsaturated fats
Saturated fats have no double bonds between carbon atoms and are usually solid at room temperature, while unsaturated fats contain one or more double bonds, making them liquid at room temperature.
What are globular proteins?
Globular proteins are compact, spherical proteins that are soluble in water and play various roles, including enzymatic activity and transport.
Describe the primary structure of proteins
The primary structure is the linear sequence of amino acids in a polypeptide chain, determining the protein’s unique characteristics.
What is the role of enzymes in proteins?
Enzymes act as catalysts to speed up biochemical reactions without being consumed in the process.
What is the function of DNA?
DNA contains genetic information that encodes the sequence of amino acids in proteins.
What is the function of RNA?
RNA acts as an intermediary that carries instructions from DNA to ribosomes for protein synthesis.
Explain the process of transcription
Transcription occurs in the nucleus where DNA is transcribed into messenger RNA (mRNA), which carries genetic information to the ribosome.
What is the genetic code?
The genetic code consists of codons, sequences of three nucleotides that correspond to specific amino acids, directing protein synthesis.
What is the function of LDL cholesterol?
LDL (Low-density lipoprotein) carries cholesterol from the liver to the cells, but excessive amounts can lead to fatty deposits in artery walls, increasing cardiovascular disease risk.
Describe HDL cholesterol
HDL (High-density lipoprotein) helps remove excess cholesterol from the bloodstream, transporting it back to the liver for excretion, thus reducing cardiovascular disease risk.
What lifestyle changes can help manage cholesterol levels?
Healthy diet, regular exercise, quitting smoking, and medications like statins can help manage cholesterol levels.
What is the function of the cell membrane?
The cell membrane regulates what enters and exits the cell, providing protection and support while maintaining homeostasis.
What are organelles?
Organelles are specialized structures within a cell that perform distinct functions, such as energy production, protein synthesis, and waste processing.
Describe the role of mitochondria
Mitochondria are the powerhouse of the cell, generating ATP (adenosine triphosphate) through cellular respiration.
What is the function of the endoplasmic reticulum (ER)?
The ER is involved in the synthesis of proteins (rough ER) and lipids (smooth ER), as well as the transport of materials within the cell.
What are ribosomes?
Ribosomes are cellular structures where protein synthesis occurs, translating mRNA into polypeptide chains.
What is the role of carbohydrates in the body?
Carbohydrates are a primary source of energy for the body, providing glucose for cellular respiration and energy production.
What are essential fatty acids?
Essential fatty acids are fats that the body cannot produce on its own, such as omega-3 and omega-6, and must be obtained from the diet.
What are the main functions of proteins?
Proteins serve structural roles, act as enzymes, transport molecules, provide immunity, and facilitate signaling within and between cells.
What is the role of insulin?
Insulin is a hormone produced by the pancreas that lowers blood glucose levels by facilitating the uptake of glucose into cells.
What are hormones?
Hormones are chemical messengers produced by glands in the endocrine system that regulate various physiological processes in the body.
What is ATP, and why is it important?
ATP (adenosine triphosphate) is the primary energy currency of the cell, providing energy for various cellular processes.
Define metabolism
Metabolism encompasses all biochemical reactions within a cell, including catabolic (breaking down) and anabolic (building up) processes.