biocell ezber

What is a cell?

Structural and functional fundamental unit of life

What characteristics define a cell?

Self-regulation

What does self replication mean?

Giving genetic information to daughter cells

What types of cells exist?

Prokaryotic and eukaryotic

What type of cells are human cells?

Eukaryotic

What are the two main types of cells?

Eukaryotes and Prokaryotes

Which organisms are prokaryotes?

Bacteria and archaea

Which organisms are eukaryotes?

Plants

What is an organelle?

An intercellular complex with its special morphology and functions

How are organelles classified?

Endomembrane bounded or non endomembrane bounded

Which organelles are endomembrane bounded?

Peroxisome

What is the function of the peroxisome?

Oxidative reactions breakdown of long fatty acid chain and neutralization of peroxides

What is the function of the lysosome?

Digestion of macromolecules using digestive enzymes

What is the function of the endoplasmic reticulum?

Storage of calcium and lipid and protein biosynthesis

What is the function of the Golgi apparatus?

Maturation

What is the function of the nucleus?

Storage of genetic material and transcription of DNA to RNA

What is the largest membrane bound organelle in mammals?

Nucleus

Which organelles are not membrane bounded?

Cytoskeleton

What is the cytoskeleton?

Network of fibrillary proteins

What are the functions of the cytoskeleton?

Maintains cell shape

What is the function of ribosomes?

Protein synthesis

What are ribosomes composed of?

A small and a large subunit

Where does mRNA bind during translation?

Between the ribosomal subunits

What is the function of the proteasome?

Digestion of cytosolic proteins

What is the function of centrioles?

Organization of the microtubule network and mitotic spindle

What are the main components of the eukaryotic cell?

Cell membrane

What does cytoplasm consist of?

Cytosol and organelles

What is a stem cell?

Immature

How do stem cells become specialized?

By differentiation

How do stem cells divide?

Asymmetrically

What are cytoplasmic inclusions?

Lipid droplets and glycogen inclusions

Can cytoplasmic inclusions perform metabolic activities?

No

What is an in vivo study?

Studying cells or organs in an intact living organism

What is the main advantage of in vivo studies?

Results closely match processes at the level of the human organism

What is the main limitation of in vivo studies?

Results are difficult to interpret because of influences from other components of the organism

What is an in vitro study?

Studying cells isolated from the organism

What is the main advantage of in vitro studies?

Rigorous control of the experiment

What is the main limitation of in vitro studies?

Results may not be the same as in vivo

What is the aim of preclinical studies?

To understand disease mechanisms and target causes of disease

Why are new drugs tested on animals?

To understand efficacy and toxicity

What are the components of preclinical studies?

Genetic testing

What is the role of genetic testing in preclinical studies?

Testing for specific mutations

What is the role of protein studies in preclinical studies?

Studying disease-causing proteins

What is the role of cell cultures in preclinical studies?

Testing new drugs on cells and tissues

What is the role of animal models in preclinical studies?

Testing new drugs on animals with disease

What are the steps of permanent microscopy specimen preparation?

Harvesting

What is the purpose of fixation?

Preserve tissue and cell architecture and prevent protein denaturation and tissue autolysis

What is used for chemical fixation in LM?

Formaldehyde

What is used for physical fixation?

Freezing

Does fixation kill cells?

Yes

Which fixatives are used for EM?

Glutaraldehyde and osmium tetroxide

What is microscopy mainly about?

Highlighting the contrast between intracellular structures

What are the main types of light microscopy?

Bright field

How is contrast enhanced in bright field microscopy?

Using conventional dyes

How is contrast enhanced in phase contrast microscopy?

By differences in how light is refracted

How is contrast enhanced in fluorescence microscopy?

Using fluorescent staining (fluorochrome)

How is magnification power calculated in a light microscope?

Magnification of objective lens × magnification of eyepiece

What is the function of the 4x objective?

Locating the specimen

What is the function of the 10x objective?

Identifying the area of interest

What is the function of the 20x objective?

Identifying tissue type

What is the function of the 40x objective?

Identifying tissue type

What is the function of the 60x objective?

Identifying cell type

What is the function of the 100x objective?

Identifying cell type

What is resolution in light microscopy?

Minimum distance at which two distinct points appear as separate entities

What factors influence resolution in light microscopy?

Refraction index

What is the physical limit of resolution in light microscopy?

0.2 μm

How are electron microscope capabilities measured?

Magnification power and resolution

What is ultrastructure?

Fine structural details visualized by electron microscopy

What is the principle of electron microscopy?

A high voltage electron source sends electron beams and electromagnetic lenses project electrons to a detector where an image is recorded

What is the first step in sample preparation for LM?

Harvesting

What is a biopsy?

Sampling of living tissue

What is a necropsy?

Sampling of postmortem tissue

What should be used during biopsy harvesting?

Fixatives

What should be used during necropsy harvesting?

Culture medium or saline solution

What is the second step in LM sample preparation?

Fixation

Why is fixation performed?

To preserve tissue architecture

What is used for chemical fixation in LM?

Formaldehyde

What is used for physical fixation in LM?

Freezing

What is the third step in LM sample preparation?

Embedding

What is embedding?

Inclusion of biological material into a solid material

What material is commonly used for embedding?

Paraffin

What is the fourth step in LM sample preparation?

Sectioning

What instrument is used for sectioning?

Microtome

How are tissues prepared during sectioning?

They are cut into thin slices

What is the fifth step in LM sample preparation?

Staining

Why is staining necessary?

To increase contrast between different cellular and tissue components

What determines how dyes bind to structures?

Biochemical properties of macromolecules

What is hematoxylin?

A basic dye

What does hematoxylin bind to?

Acids

What color does hematoxylin produce?

Purple

What structure is stained by hematoxylin?

Nucleus

What is eosin?

An acidic dye

What does eosin bind to?

Basic structures

What color does eosin produce?

Pink

What structure is commonly stained by eosin?

Cytoplasm

What are the components of H&E staining?

Hematoxylin and eosin

What is Transmission Electron Microscopy (TEM)?

Electron microscopy technique used to study internal ultrastructure of cells and small particles

What fixation methods are used in TEM?

Chemical fixation and physical fixation by freezing

At what temperature can physical fixation for TEM be performed?

−190°C

What chemical fixation method is used for cells and tissues in TEM?

Resin embedding