biocell full q

Describe what is a cell and present its caractaristics

A cell is the structural and functional fundamental unit of life which is characterized by having self-regulation

Describe what types of cell there are

There are 2 main types of cells Eukaryotes and Prokaryotes

Describe an organelle and specify its classification

An intercellular complex which has its special morphology and functions. Can be endomembrane bounded (peroxisome

What are membranebound organelles and their main functions

Peroxisome: oxidative reactions breakdown of long fatty acid chain. Neutralization of peroxides. Lysosome: has digestive enzymes function is to digest macromolecules. Endoplasmic reticulum: storage of calcium

What are organelles without membranes and their functions

Cytoskeleton- network of fibrillary proteins

What are the main components of the eukaryotic cell

Cell membrane

What is a specialized cell (stem cell)

Immature

What are cytoplasmic inclusions

Lipid droplets and glycogen inclusions. They cannot perform metabolic activities

Explain what is in vivo studies

their advantages and limitations

results we obtain are close match for studies process at level of human organism. Disadvantage

results of experiments are difficult to interpret

because of the influences of other components in organisms

Explain what is in vitro studies

their advantages and limitations

Define pre clinical studies and list their main components

Preclinical studies aim to understand the mechanism of the diseases and target causes of the diseases. A new drug is always tested on animals to understand the efficacy and toxicity. Genetic testing. Protein studies. Cell cultures. Animal models

Explain the role and importance of pre-clinical studies in drug development

To understand mechanisms of diseases and not symptoms targeted by drugs. Genetic testing (for specific mutations). Protein study (structure of various disease causing proteins). Cell cultures in vitro (testing new drugs on cells/tissues). Animal models (testing new drugs on animals that have diseases)

What are the steps of permanent microscopy specimens

1.Harvesting 2. Fixation 3. Embedding 4. Sectioning 5. Staining 6. Mounting and Labeling

Explain the method of fixation

To preserve the architecture of tissues+cells

Talk about HE stains. Make sure you mention its components

results and mechanism of staining

Name the types of light microscopy

Microscopy- all about highlighting the contrast between intracellular structures. Bright field - contrast is usually enhanced using conventional dyes. Phase contrast - contrast is enhanced by differences in how light is refracted. Fluorescent microscope - contrast is enhanced by using fluorescent staining (florochrome)

How is the magnification power of a light microscope calculated

Magnification of objective lens x magnification of eye piece

What are the common types of objectives used in light microscopy and their functions

4x (locating). 10x (area of interest). 20x/40x (identify tissue type). 60x/100x (identify cell type)

What is the definition of resolution in light microscopy (LM)

Minimum distance at which two distinct points of a specimen appear as separate entities

What factors does the resolution of a light microscope depend on

Refraction index

What is the physical limit of resolution in light microscopy

0.2𝜇 (diffraction limit)

How are the capabilities of electron microscopes measured

Magnification power

Explain the principle of electron microscopy and define ultrastructure

There’s a high voltage electron source which send electron beams and there are electromagnetic lenses electrons are projected to the detector and an image is recorded

Explain the working principle of Transmission Electron Microscopy (TEM) and the meaning of electron dense and electron lucent areas

The e- beam is emitted continuously by a source which’s heated by a high voltage current. It has a vacuum inside so that e- won’t collide with air molecules. Electromagnetic lenses guide the flow of e- through specimen

What is an antibody and who produces it in the human body

A y shaped protein produced by b lymphocytes in response to an antigenic stimulus (bacterial/viral) which binds to a specific antigen through spatial complementarity

What is an antigen

Any protein or non-self peptide capable of stimulating production of antibodies

List two methods that use antibodies

Two methods that use antibodies are immunolabelling and ELISA (enzyme linked immunosorbent assay)

What is immunolabelling and how does it work

Immunolabelling is based on specific interactions between an antigen and an antibody. Antibodies are tagged with a detection label that allows visualization or measurement of the antigen

What types of detection labels are used in immunolabelling

Detection labels used in immunolabelling include: Enzymes that act on a substrate to produce a colored compound

What is ELISA and what is its principle

ELISA is a method in which the detection antibody is conjugated with an enzyme. It is an enzyme (labelled antigen) antibody reaction in which the amount of antigen can be quantified by the intensity of the color generated from the enzymatic reaction

What is the central dogma of molecular biology

Its the statement that represents genetic information flowing in one direction

List two methods used to study nucleic acids

PCR (Polymerase Chain Reaction). Gene sequencing

What is PCR and what is it used for

Basically it is a method used to obtain a large number of copies of a specific gene or DNA sequence

RT-PCR

RT-PCR works by detecting RNA through its conversion into DNA and subsequent amplification. First

What is gene sequencing and what is it used for

Gene sequencing is a method that determines the precise order of bases (A

List two differences between nucleic acids and proteins

Nucleic acids (DNA

What are the primary

secondary

What are the main functional classes of proteins

Major protein classes include enzymes such as helicases and polymerases

What is cell culture

Cell culture is a technique that enables the maintenance of viable cells in homogeneous populations using specially designed incubators with controlled temperature

Why is cell culture useful in research

Cell culture is the simplest and most frequently used in vitro method to study living cells and their functions. It is also useful for cytotoxicity testing and for studying molecular mechanisms

Argue why an animal model is better than a cell culture

Animal models are superior to cell cultures because they have a higher similarity to the human genome

What are the main types of electron microscopes

The main types of electron microscopes are Transmission Electron Microscopy (TEM) and Scanning Electron Microscopy (SEM)

What is Transmission Electron Microscopy (TEM) and what fixation methods are used

Transmission Electron Microscopy (TEM) is an electron microscopy technique used to study the internal ultrastructure of cells and small particles. Fixation methods used in TEM include chemical fixation at room temperature and physical fixation by freezing at −190 °C

What are the types of chemical fixation used in TEM and what are they used for

Chemical fixation in TEM includes: Resin embedding → for cells and tissue. Negative staining → is used for small particles such as viruses and proteins

What are the types of physical fixation used in TEM and what are they used for

Physical fixation in TEM is performed by freezing at −190 °C and includes: High pressure freezing → used for cells and tissue. Single particle cryo EM → used for small particles such as viruses and proteins

What is Scanning Electron Microscopy (SEM)

Scanning Electron Microscopy (SEM) is a type of electron microscopy used to examine the surface morphology and three dimensional structure of specimens

Sample preparation for light microscopy includes

1.Harvesting: biopsy=sampling of living tissue

What is a specialized cell and how does specialization allow it to perform a specific function

It’s a cell that has developed certain organelles and structural features to optimally perform a specific function. Specialization allows cells to carry out their roles more effectively. Ex:intestinal absorptive cell

Explain immunohistochemistry and its role as an immunolabeling technique

Immunohistochemistry is an immunolabeling technique that uses specific antibodies to detect antigens in tissue sections. The antibodies are linked to visible markers

Describe the ultrastructure of a mobile cilium in cross section

Axoneme: 9 peripheral microtubule doublets + 2 central microtubules. Basal Body: 1 centriole

Describe the structure and functions of Rough endoplasmic reticulum (RER)

Membrane is continuous with outer membrane of nuclear envelope which’s connected to nucleus. Studded with ribosomes. Functions in synthesis and processing of some proteins (membrane proteins

Describe the structure and functions of Nuclear envelope

Formed by inner and outer nuclear membrane + perinuclear space (nuclear envelope lumen). Double membrane surrounding nucleus. Only present in interphase. Maintains nuclear integrity

Describe the structure and functions of Euchromatin

Pale stained in light microscopy

What is an in vitro method and what are its advantages in cell biology studies

A method used to study living cells

What is meant by the term "structure" in microscopy

Morphological details and organization of cells or tissues that can be visualized under the microscope. It describes what can be seen

Explain the principle of PCR and discuss its clinical applications

To obtain a number of copies of a gene

Why is fixation necessary after tissue harvesting? What happens if fixation is delayed

Preserves the tissue as close as possible to its living state. If fixation is delayed

Explain the principle and applications of X-ray crystallography

X-ray crystallography is a technique used to determine the three-dimensional arrangement of atoms within a crystal. X-rays are diffracted by the crystal

How can you recognize an electron microscopy image and identify a nucleus in such an image

Recognized by its high resolution and grayscale appearance

Describe the structure and function of ribosomes

A ribonucleoproteic organelle acting in protein biosynthesis. Location: free in cytosol+attached to RER. Has 2 subunits: large one+ small one

Explain the role of mitochondria in cellular energy production

ATP synthesis

Discuss the functions of the cytoskeleton

including intracellular transport

Why is the cell considered the basic self-regulating unit of life

The cell is considered the basic self-regulating unit of life because it can independently control its internal environment

What is passive transport and how does it differ from active transport

Passive transport is the movement of molecules across a membrane without the use of energy and occurs down a concentration gradient. Active transport requires energy

Explain how the plasma membrane forms a selective barrier between intracellular and extracellular environments

The plasma membrane forms a selective barrier through its hydrophobic phospholipid bilayer

Describe the mechanisms by which cells communicate with one another

Cells communicate through chemical signals or by converting physical stimuli into chemical signals. Signaling molecules bind to receptors

Explain the central dogma of molecular biology

The central dogma of molecular biology states that genetic information flows from DNA to mRNA through transcription and from mRNA to protein through translation

Describe the endocytic pathway and its relationship to lysosomal digestion

The endocytic pathway begins with the internalization of extracellular material into vesicles. These vesicles fuse with endosomes

What is de novo formation of peroxisomes

Formation of a precursor vesicle in the endoplasmic reticulum followed by import of peroxisomal proteins

How are new mitochondria formed

New mitochondria arise by growth and division of pre-existing mitochondria

What role do small GTP-binding proteins (GTPases) play during translation

Small G proteins participate in all stages of translation

Compare prokaryotic and eukaryotic cells emphasizing DNA organization

Prokaryotic cells usually contain circular DNA not associated with histones

What are gap junctions and what is their functional significance

Gap junctions are communication junctions that allow the transfer of ions and small molecules between adjacent cells

Why do lysosomes maintain an acidic internal pH

The acidic environment is necessary for the activity of lysosomal hydrolases

Describe the structure and functions of the cytoskeleton

Cytoskeleton is composed of actin filaments

What is the significance of promoter methylation in gene regulation

Promoter methylation leads to inactivation of gene transcription

What is exocytosis and what role does it play in secretion

Exocytosis is the final step of the secretory pathway and allows release of vesicle contents outside the cell

Explain how extracellular signals are transmitted into the cell

Extracellular signals bind receptors

Describe the barrier function of the plasma membrane

The hydrophobic phospholipid bilayer acts as a barrier restricting passage of many substances while allowing selective transport

What is facilitated transport and how is it mediated by carrier proteins

Facilitated transport is passive transport mediated by carrier proteins or channels

How are newly synthesized proteins targeted and transferred to the rough endoplasmic reticulum

Signal recognition particle binds the N-terminal signal sequence and directs the ribosome-protein complex to the rough endoplasmic reticulum

What is a cell-cycle checkpoint and why is it important

A cell-cycle checkpoint is a regulatory point at which the cell either proceeds through the cycle or stops progression

Describe the structure and functions of the nuclear envelope

Formed by inner and outer nuclear membrane and perinuclear space. Double membrane surrounding the nucleus. Present during interphase. Maintains nuclear integrity

Explain the detoxification functions of the smooth endoplasmic reticulum

Smooth endoplasmic reticulum converts water-insoluble substances into water-soluble forms that can be excreted

Discuss the structure and functions of cadherins and their role in cell adhesion

Cadherins are cell adhesion proteins involved in intercellular junctions

What is the clinical significance of the mitochondrial genome

Mutations in mitochondrial DNA can cause severe diseases and are maternally inherited

Compare primary and motile cilia and discuss their functions

Primary cilia are involved in sensing and responding to extracellular signals. Motile cilia are involved in movement

Explain how antibodies can promote phagocytosis by macrophages

Macrophages recognize antibody-coated targets through Fc receptors and phagocytose them

What mechanisms are responsible for the two-dimensional fluidity of the cell membrane

Lateral and rotational movement of membrane lipids

Discuss the functions of the nucleolus

Ribosome biogenesis and assembly of signal recognition particles

How do lysosomes participate in cell signaling

Lysosomes terminate signaling by degrading signaling molecules

What are lysosomal storage diseases and how do they develop

Lysosomal storage diseases develop because of deficiencies in lysosomal enzymes leading to accumulation of undigested substrates

Explain the relationship between the genome and the proteome and why the proteome is more complex

The proteome is more complex than the genome because post-transcriptional and post-translational modifications generate more protein diversity than the number of genes alone