CELL: FUNDAMENTAL UNIT OF LIFE

-     A basic unit of life, it possesses a highly organized structure that enables it to carry out its vital functions.

STRUCTURE AND BASIC COMPONENTS

- These components work together to maintain cellular homeostasis and perform essential life act

CELL MEMBRANE

-        The cell membrane surrounds the cell and is a selective barrier between the interior and the exterior.

-        Its primary role lies in regulating the passage of substances, including nutrients and waste materials.

-        Within it, specialized proteins are crucial in facilitating molecular transport and cellular communication.

CELL NUCLEUS

-        An organelle that houses DNA, located in the center of eukaryotic cells.

-        Its primary function is to store and safeguard genetic information, controlling gene expression and DNA replication.

-        It also contains the nucleolus, which is involved in ribosome synthesis.

CHROMOSOME

-        The prokaryotic chromosome usually consists of a single, long, supercoiled, circular DNA molecule, which serves as the control center of the bacterial cell. It is capable of duplicating itself, guiding cell division, and directing cellular activities

CYTOPLASM

-        It plays a crucial role in biochemical reactions, energy production, and substance transport. Essential for cellular metabolism, it provides structural support to the cell

STRUCTURE AND BASIC COMPONENTS

- These components work together to maintain cellular homeostasis and perform essential life act

                   
RIBOSOME

-        Ribosomes are essential organelles for cellular functioning and survival.

-        They synthesize proteins using the genetic information from messenger RNA (mRNA), which is crucial for cellular structure, function, and regulation.

-        Ribosomes are located in the cytoplasm and the rough endoplasmic reticulum.

MITOCHONDRIA

-        Present in eukaryotic animal and plant cells. Their primary function is energy generation through cellular respiration (ATP production).

-        The double membrane of mitochondria allows for the organization of various stages of the respiratory chain, making it crucial for cellular function and survival.

ENDOPLASMIC RETICULUM

-        A network of interconnected membranes that extends from the nuclear membrane to the cell membrane. It plays a fundamental role in the transport, processing, and distribution of proteins and lipids within the cell.

There are two main types of ER: 

●              The Rough Endoplasmic Reticulum is studded with ribosomes and is involved in the synthesis and modification of proteins.

●              The Smooth Endoplasmic Reticulum (SER) specializes in lipid synthesis, carbohydrate metabolism, and detoxification.

-        Exclusive to plant cells and photosynthetic organisms, chloroplasts carry out photosynthesis, converting solar energy into chemical energy.

-        During photosynthesis, they synthesize glucose and other organic compounds using carbon dioxide and water, releasing oxygen as a byproduct.

-        They are responsible for the crucial production of oxygen that sustains the planet.

-        It involves breaking down molecules and unwanted materials, enabling the recycling of nutrients and cellular maintenance.

-        Key in the processing and packaging of proteins and lipids produced in the endoplasmic reticulum.

-        It synthesizes carbohydrates and lipoproteins and is essential for maintaining the cell's internal balance and facilitating communication with the outside.

-        Composed of a series of flattened sacs called cisternae, it acts as the 'shipping center' of the cell, sorting and packaging proteins into vesicles for transport and distribution.

-        To carry out vital functions and necessary metabolic processes essential for the proper functioning of the cell and/or organism.

-        They contain digestive enzymes that break down molecules and unwanted cellular materials.

-        They facilitate cellular digestion, by disposing of waste, recycling nutrients, and defending against pathogenic invasions.

-        They contain enzymes that degrade hydrogen peroxide and toxic compounds, thereby protecting the cell from oxidative damage.

-        Additionally, they play a role in the synthesis and degradation of lipids and bile acids, regulating lipid metabolism and overall homeostasis.

- have a rigid structure, and are not associated with motility.

-        Maintaining cellular shape, and enabling cellular movement and division, are essential for its functioning and survival.

-        It is composed of protein filaments (microtubules, microfilaments, and intermediate filaments) and provides support and enables movement in eukaryotic cells.

-        Its specific functions encompass stability, intracellular transport, and contraction.

Furthermore, it regulates cellular shape and plays a role in division, migration, and communication.

-        The cell wall is, a specialized form of the extracellular matrix that surrounds every cell of a plant. The cell wall is responsible for many of the characteristics that distinguish plant cells from animal cells.

-        The rigid exterior cell wall that defines the shape of bacterial cells is chemically complex

-        The structure of bacterial cell walls is quite different from the relatively simple structure of eukaryotic cell walls.

-        Specialized structures for movement. They are elongated and enable locomotion in liquid environments, whereas cilia are shorter and create coordinated flow on the cell surface.

-        Composed of microtubules in a '9+2' pattern, they are essential for sperm motility.

-        not highly organized

-        not firmly attached to the cell wall

-        It easily detaches from the cell wall and drifts away

-        genus Pseudomonas

-        highly organized and firmly attached to the cell wall

-        consist of polysaccharides, which may be combined with lipids and proteins, depending on the bacterial species

-        chemical composition of capsules is useful in differentiating among different types of bacteria within a particular species

-        hair-like structures, most often observed on

Gram-negative bacteria

-        polymerized protein molecules called pilin

-        thinner than flagella

-        They manage nutrients, eliminate waste, and regulate metabolic processes.

-        Membrane-bound organelles found in plant cells and some animal cells. They store nutrients, water, ions, and waste materials, regulating turgor pressure and osmotic balance.

-        Vacuoles can also be involved in the digestion of substances and serve as a defense mechanism against predators by containing toxins.

-        Membranous vesicles that transport specific materials between organelles and the cell membrane.

-        Vesicles: They transport materials from the endoplasmic reticulum and the Golgi apparatus to other destinations.

-        Endosomes: They capture and distribute materials for degradation, recycling, or their incorporation into metabolic pathways.

➢    lack the genes and enzymes necessary for energy production

➢    depend on the ribosomes, enzymes, and metabolites(“building blocks”) of the host cell for protein and nucleic acid production

-        A typical virion consists of a genome of either DNA or RNA, surrounded by a capsid (protein coat), which is composed of many small protein units called capsomeres (or capsomers).

-        Double-stranded DNA

-        Single-stranded RNA

-        Single-stranded DNA

-        Double-stranded RNA

-        During sporulation, a copy of the chromosome and some of the surrounding cytoplasm becomes enclosed in several thick protein coats.

-        Polyhedral (many-sided)

-        Helical (coiled)

-        Bullet shaped

-        Spherical

-        microscopic organisms that can infect various life forms, including humans, animals, and plants.

They consist of genetic material (DNA or RNA) enclosed in a protein coat. Despite not being classified as living organisms, viruses have significant impacts on global health and ecosystems.

-        Viruses are said to have five specific properties that distinguish them from living cells:

➢    the presence of DNA or RNA

➢    unable to replicate (multiply) on their own

➢    do not divide by binary fission, mitosis, or meiosis.

-        Determined by number of casomeres

-        Presence or absence of envelope

-        Type of host and type of disease

-        Target cell

1.     Coevolution Theory

2.     Retrograde Evolution Theory

3.     Escape Gene Theory

-        Spherical

-        Filamentous

-        Complex

-        Cancer-causing virus

-       

HIV, the cause of AIDS, is an enveloped, single-stranded RNA virus

-       

RNA

-       

DNA

-        Virulent

-        Temperament

-   An extremely large double-stranded DNA virus, called Mimivirus, was recovered from amoebas. Megavirus is an even larger double-stranded DNA virus was discovered in a water sample collected in 2010 off the coast of Chile.

-        A latent infection is an infection by an organism that lies hidden or dormant (inactive) in the body. Latent Virus Infections

-        are usually transmitted via insects (e.g., aphids, leaf hoppers, and whiteflies); mites; nematodes (round worms) infected seeds, cuttings, and tubers; and contaminated tools (e.g., hoes, clippers, and saws).

-       Bacteria

-      

Archaea

-        Antivirals are medications that help your body fight off certain viruses that can cause disease. Antiviral drugs are also preventive. They can protect you from getting viral infections or spreading a virus to others.

-        cell morphology

-        motility

-        staining reaction

-        atmospheric requirements

-        biochemical and metabolic activities

-        specific enzymes

-        pathogenicity

-        genetic composition

-        coccus

-        bacillus

-        spirilla

-        Vibrio spp

➢    V. cholerae

➢     V. parahaemolyticus

-          Some bacteria may lose their characteristic shape because adverse growth conditions (e.g., the presence of certain antibiotics)

-          Ability to exist in a variety of shapes

-          Methylene blue

-          size, shape, and morphologic arrangement

-          Capsule stains

-          Flagella stains

-         

Endospore stains

-          Rod-shaped

➢    diplobacilli

➢    streptobacilli

➢    coccobacillia

-          Examples

➢    Enterobacter

➢    Escherichia

➢    Proteus

➢    Salmonella

➢    Pseudomonas aeruginosa

➢    Corynebacterium diphtheriae

-          Note: The term "Bacillus" is also the name of a genus (Bacillus anthracis) that, among many other genera, falls within the class Bacilli. The word "bacillus" is also a generic term to describe the morphology of any rod-shaped bacterium.

-         

Gram Stain

-          Acid-fast stain

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-         

Cocci

➢    Generally nonmotile

-          Bacilli & spirochetes

➢    Generally with flagella

-          demanding nutritional requirements

-         

Size of colonies: microbes rate of growth

-          Bacteria

➢    waste products

➢    secretions (enzymes)

➢    production of gases

-          Due to

➢    possess capsules, pili, endotoxins

➢    secrete exotoxins & exoenzymes

-          gram-negative

-          obligate intracellular pathogens (leaky cm)

-          do not grow on artificial culture media

-          Howard Ricketts

-          arthropod-borne diseases

-         

spotted fever rickettsiosis

-          energy parasites

-          obligate intracellular pathogens

-          Chlamydia trachomatis, Chlamydophila pneumoniae, and Chlamydophila psittaci

-        Phycology or algology

-        cytoplasm, call wall (usually), cell membrane, nucleus, plastids, ribosomes, mitochondria, golgi bodies

➢    Some:

➢    Pellicle (thickened cell membrane);

➢    stigma/eyespot (light-sensing organelle)

➢    flagella

-          smallest

-          Lack cell walls

-          may be free-living or parasitic and pathogenic

-          resistant to treatment with penicillin and other antibiotics

-          Use light as energy source

-          anoxygenic (P, G)

-          thylakoids

-          phycobilisomes

-          Tiny, unicellular

-          FW and SW

-          Have silicon dioxide in their cell walls

-          Unicellular

-          Photosynthetic algae

-          Production of oxygen l

-          Links in food chain

-          include desmids, Spirogyra,

-          Chlamydomonas, Volvox, and Euglena

-          More closely related to eukaryotes genetically

-          Vary in shape extremophiles with cell wall

-​

-          Photosynthetic

-          chloroplasts,

-            stores energy in the form of starch.

-          the presence of a cytostome

-            With its stigma, it can sense light;

-          With its flagellum, it can swim into the light.

-          possess a pellicle, which serves the same function as a cell wall—protection.

-          Protozoology ; protozoologist

-          Most are unicellular

-          Most are free-living found in soil and water

-          Cell membrane, nuclei, ER. Mitochondria, golgi bodies, lysosomes. Centrioles, food vacuoles

➢    Some :

➢    possess pellicles, cytosomes. contractile vacuole

➢    pseudopodia, cilia, flagella

-          Mycology

-          Saprophytic fungi

-          Production of cheese, beer, wine, and even drugs and antibiotics

-          Garbage disposers of nature

-          Original recyclers

-          Cell wall contains chitin

-          Many are unicellular (yeast); others grow as filaments called hyphae which intertwine to form mycelium or thallus

-          Septae hyphae: cytoplasm within the hypha is divided into cells by cross-walls or septa

-          Aseptate hyphae: not divided into cells

-          Moved by pseudopodia

-          Phagocytosis

-          Pinocytosis

-          By budding, hyphal extension or formation of spores

-         

Most complex

-          Balantidium coli

-          Examples of pond water ciliates are Didinium, Euplotes, Paramecium, Stentor, and Vorticella spp.

-          Trypanosoma brucei: African sleeping sickness

-          Trypanosoma cruzi: s American

-          trypanosamiasis (Chagas disease)

-          Trichomonas vaginalis: trichomaniasis

-       Pollution indicator

-       Succession

-       Soil formation

-       Nitrogen fixation

-       As staple food

-       As continent

-       As food preservative

-        Anti-inflammatory

-        Anti-microbial

-        Anti-oxidant

-        Anti-cancer

-        Wound healing

-        Source of dye

-        Pharmaceuticals

-        Cosmetics

-        Perfumery

-        bioremediation