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Prokaryotic and Eukaryotic Cells: A Comparative Study, Study notes of Genetic Engineering

University of Houston – Downtown (UHD)Genetic Engineering

A comparative analysis of prokaryotic and eukaryotic cells, including their structures, organelles, and modes of transportation and reproduction. It also discusses the importance of bacteria, archaea, and algae in various environments and industries.

Typology: Study notes

2021/2022

Uploaded on 09/12/2022

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MAJOR GROUPS OF MICROBES
MICROBES
• The term microbe is short for microorganism which means small
organism – observed with a microscope
• Over 99% of microbes contribute to the quality of human life
• A small minority cause disease – in humans by sheer numbers or
producing powerful toxins
• The major groups of microbes are Archaea bacteria, , algae, fungi,
protozoa & viruses
• In terms of numbers, microbes represent most of the diversity of life
on Earth and are found in every environment.
BENEFICIAL VS HARMFUL MICROBES
• Most are beneficial (over 99%) contribute to the quality of human life
• They live in every environment on earth
• Microbes are important in ecological systems
• They are important to biogeochemical cycles
• Human digestion depends upon them
• They are important to the food industry and the productions of many products
• Microbes help with wastewater and oil spill cleanup
• A small minority of microbes cause disease
CELLULAR LIFE - All cells have the following:
• Has a membrane that separates the cell from the outside world
• Contains a nucleic acid as its genetic material (DNA or RNA)
• Use their genetic material to produce protein – structural or functional as enzymes and hormones
• Are composed of basic chemical as carbohydrates, proteins, fats, nucleic acids, vitamins, &
minerals
• Regulate the flow of nutrients and wastes entering and leaving the cell
• Reproduce and are the result of reproduction
• Require a source of energy
• Interact with their environment
ACELLULAR VS CELLULAR
• Acellular – Viruses do not have cellular components, nor do they grow or metabolize organic
materials. They generally consist of a piece of nucleic acid encased in protein which must use the
cellular components of a living cell to reproduce. Prions (proteinaceous infectious particles) are
infectious agents composed primarily of protein which induce the existing polypeptides in host
cells to take on its form.
• Cellular – bacteria and Archaea are prokaryotic cells while algae, fungi, and protozoa have
eukaryotic cells.
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MAJOR GROUPS OF MICROBES

MICROBES

  • The term microbe is short for microorganism which means small organism – observed with a microscope
  • Over 99% of microbes contribute to the quality of human life
  • A small minority cause disease – in humans by sheer numbers or producing powerful toxins
  • The major groups of microbes are Archaea bacteria, , algae, fungi, protozoa & viruses
  • In terms of numbers, microbes represent most of the diversity of life on Earth and are found in every environment. BENEFICIAL VS HARMFUL MICROBES
  • Most are beneficial (over 99%) contribute to the quality of human life
  • They live in every environment on earth
  • Microbes are important in ecological systems
  • They are important to biogeochemical cycles
  • Human digestion depends upon them
  • They are important to the food industry and the productions of many products
  • Microbes help with wastewater and oil spill cleanup
  • A small minority of microbes cause disease CELLULAR LIFE - All cells have the following:
  • Has a membrane that separates the cell from the outside world
  • Contains a nucleic acid as its genetic material (DNA or RNA)
  • Use their genetic material to produce protein – structural or functional as enzymes and hormones
  • Are composed of basic chemical as carbohydrates, proteins, fats, nucleic acids, vitamins, & minerals
  • Regulate the flow of nutrients and wastes entering and leaving the cell
  • Reproduce and are the result of reproduction
  • Require a source of energy
  • Interact with their environment ACELLULAR VS CELLULAR
  • Acellular – Viruses do not have cellular components, nor do they grow or metabolize organic materials. They generally consist of a piece of nucleic acid encased in protein which must use the cellular components of a living cell to reproduce. Prions ( pr oteinaceous i nfectious particles) are infectious agents composed primarily of protein which induce the existing polypeptides in host cells to take on its form.
  • Cellular – bacteria and Archaea are prokaryotic cells while algae, fungi, and protozoa have eukaryotic cells.

PROKARYOTIC VS EUKARYOTIC CELLS

Comparison

  • Prokaryotic – single celled microorganism (archaea and bacteria) with nuclear material but no nuclear membrane or membrane bound organelles Eukaryotic Animal Cell Eukaryotic Plant Cell
  • Eukaryotic – most cells – with organized nucleus and membrane bound organelles Surface of Cell: - Cell Wall – commonly found in plants cells – protection & support - Plasma Membrane – control of substances coming in and out - Cilia - sweep materials across the cell surface - Flagellum - enables a cell to propel and move in different directions Cytoplasm – between plasma membrane and nucleus – many organelles - Endoplasmic reticulum (ER) is the passageway for transport of materials within the cell - Synthesis of lipids – modification of newly formed polypeptide chains - Ribosomes are the site of protein synthesis - Golgi apparatus - Final modification of proteins & lipids Packing of materials for secretion of the cell - Mitochondria are the site of aerobic cell respiration-ATP production - Lysosomes contain enzymes to digest ingested material or damaged tissue - Chloroplasts – store chlorophyll – photosynthesis light reaction - Vacuoles – storage – increase cell surface area - Centrioles - organize the spindle fibers during cell division - Cytoskeleton – cell shape, internal organization, cell movement & locomotion

are termed endospores or bacterial spores. Bacterial spores can exist at extreme environments for centuries. Cysts – Resistant cells formed by some protozoa.

RELATIVE SIZE OF MICROBES

1000 millimeters (mm) = 1 meter (m) 1000 micrometers (μm or mcm) = 1 millimeter (mm) 1000 nanometers (nm) = 1 micrometer (mcm) Relative Sizes of Viruses and Prions – must be viewed with electron microscopes

MAJOR GROUPS

PRIONS - acellular General Characteristics - ultramicroscopic proteinaceous infectious particles Importance - associated with a number of diseases characterized by loss of motor control, dementia, paralysis, wasting and eventually death

  • Creutzfeld-Jacob disease (CJD) in humans
  • Gerstmann-Straussler-Scheinker syndrome (GSS) in humans
  • Alpers syndrome ( in infants),
  • Fatal Familial Insomnia (FFI) in humans
  • Kuru in humans
  • Scrapie in sheep,
  • Bovine Spongiform Encephalopathy (BSE) or Mad Cow Disease in cattle
  • Chronic Wasting Disease (CWD) in wild ungulates such as Mule deer and elk VIRUSES – acellular General Characteristics
  • Are acellular
  • Consists of a piece of nucleic acid (DNA or RNA) encased in protein and in some cases a membrane-like envelope
  • They come in many shapes
  • Are parasites - found anywhere there are cells to infest
  • Are small – ranging from 20 – 400 nm
  • Exist to reproduce – must take over a suitable host cell
  • Uses the cell machinery of the host cell to reproduce Mode of Transportation – outside of a living cell a viral particle is inactive Mode of Reproduction – viruses must infest a living cell and use the cellular machinery of the infested cell in order to reproduce. The genetic material can mutate.

BACTERIA – prokaryotic General Characteristics

  • Consist of only one cell – a prokaryotic cell
  • Live in all environments – even above boiling point and below freezing point
  • Are typically smaller than eukaryotic cells
  • Are basically three shapes – spherical , rod, and spiral or helical
  • Exist as individuals or cluster together to form pairs, chains, squares, or other groupings
  • Some are photoautotrophic - make their own food as plants and give off oxygen
  • Some are chemoautotrophic - synthesize their own food using energy from chemical reactions – important Composite of a bacteria cell
  • for recycling in nitrogen and sulfur cycles
  • Some types are also aerobic – use oxygen for respiration while others are anaerobic
  • Some form spores which allow them to survive severe environmental conditions
  • Bacterial spores can exist at extreme environments for centuries. Mode of Transportation - Some have flagella - rotates like a tiny outboard motor, others secrete a slime layer and move over surfaces like slugs, while others are immobile. Mode of Reproduction - grow to a fixed size then reproduce through binary fission, a form of asexual reproduction, resulting in the formation of two bacterial cells that are genetically identical. Importance of Bacteria
  • Typically 40 million bacteria in a gram of soil and a million bacteria in a milliliter of fresh water
  • Cyanobacteria have chlorophyll and carry on photosynthesis – are primary producers and along with algae provide large amounts of oxygen
  • Vital in recycling nutrients – decomposers
  • In many steps of biogeochemical cycles depending on these
  • Used as pesticides
  • Used to degrade a variety of organic compounds in waste processing
  • Used to clean up oil spills
  • Used with yeasts and molds in the preparation of an number of kinds of food
  • Important agents for genetic engineering
  • Used in industry to produce a number of products
  • Can be important agents for disease

GRAM + AND GRAM BACTERIA

Gram positive bacteria

  • stain purple under Gram stain
  • have a thick bilayer wall of the polymer peptidoglycan. Gram negative bacteria
  • stain red
  • have a thin layer of this polymer and an additional lipopolysaccharide outer layer, LPS,
  • often endotoxic - capable of initiating inflammation and cell-mediated immune responses
  • e.g., Salmonella , Shigella , and Escherichia. BACTERIAL SHAPES
  • • • • • • • • • • • • • • • • • • • • • •
  • bacillus is rod-shaped
  • coccus is ball-shaped
  • spirilium is spiral-shaped
  • vibrio is comma-shaped
  • cocco-bacillus is ovoid-shaped
  • other combinations

ANIMAL-LIKE PROTISTS (PROTOZOA) – eukaryotic General Characteristics

  • Protozoa means “little animal” – act like tiny animals – Eukaryotic
  • Vary greatly in shape and size
  • Size varies from 10 to 50 mcm but some are as large as 1000 mcm
  • Most prefer a pH near normal (pH of 7)
  • Unicellular eukaryotic microorganisms lacking a cell wall
  • Some have cells surrounded by hard shells
  • Most have a single nucleus
  • Some have both a macronucleus and one or more micronuclei.
  • Contractile vacuoles may be present to remove excess water
  • Heterotrophic - hunt other microbes for food
  • Food vacuoles are often observed – obtain large food particles by phagocytosis
  • Mainly feed on bacteria, also other protozoa and some algae
  • Digest food in digestive organelles
  • Some protozoa as Euglena have chlorophyll and can photosynthesize
  • Most are found in moist environments as freshwater, salt water and soil
  • Most species are aerobic but a few anaerobic species are found in human intestines and animal rumen Mode of Transportation – Most can move independently They are organized by mode of transportation
  • Ciliates – hair-like cilia (Paramecium)
  • Amoebaes – foot-like pseudpods (Amoeba)
  • Flagellates – whip-like flagella (Euglena) Amoeba Mode of Reproduction
  • They can reproduce by binary fission or multiple fission
  • Some produce sexually
  • Still others reproduce using a combination of both
  • Some types alternate between a free-living vegetative form known as a trophozoite and a resting form called a cyst.
  • The protozoan cyst is like the bacterial spore can resists harsh conditions in the environment.
  • Many protozoan parasites are taken into the body in the cyst form.
  • In the trophozoite stage, they feed actively Importance of Protozoa
  • Most are not harmful – a few are harmful
  • Important as zooplankton , the free-floating aquatic organisms of the oceans
  • Found at the lower end of many food chains and food webs
  • Both herbivores and consumers
  • Help control bacterial populations
  • Important food source for macro-invertebrates
  • Certain protozoa are parasites and can cause dysentery and malaria

FUNGI – eukaryotic General Characteristics

  • Single celled as yeast or multicellular clusters as molds & mushrooms
  • Cellular level, more like animals than plants
  • Cell walls contain chitin
  • Heterotrophic - can’t synthesize their own food – secrete digestive enzymes into surrounding environment to break down large organic molecules to yeast with buds simple molecules that they can absorb
  • Most are aerobic, some are facultative anaerobic (ex. yeast) and some are anaerobic
  • Can’t tolerate high temperatures but some types can tolerate high sugar concentration, high acid environments, and extremely cold temperatures
  • Grow best under conditions that are somewhat acidic – often prefer pH of 5
  • Multicellular ones form filament like strands – hyphae
  • Cross walls between fungal cells called septa and some species lack these septa as bread mold
  • Grow best in slightly acidic environment – can grow in low moisture
  • Live in soil, on plants & animals, in fresh & salt water
  • One teaspoon of topsoil has about 120,000 fungi Mode of Transportation
  • Non- mobile Mode of Reproduction
  • Sexual and asexual modes of reproduction
  • Form sexual and asexual spores
  • Yeast form buds for asexual reproduction Importance of Fungi
  • Baker’s yeast for bread and brewing
  • Many fungi are edible and are cultivated worldwide
  • Important as decomposers in the ecosystem recycling nutrients
  • In symbiotic relation (mutualism) with algae or Cyanobacteria to form lichens
  • Form mycorrhizal associations with plant roots which are essential to the growth and health of plants - help absorb phosphorus from the soil
  • Some fungi are used as pesticides
  • Used as biofertilizers
  • Used in the manufacture of dairy products, pharmaceuticals as antibiotics, vitamins, enzymes, vaccines
  • Used for Genetic Engineering
  • Food Spoilage - Can grow on bread, fruit, cheese, and other foods even when refrigerated
  • Ruin ¼ to ½ of fruits & vegetables per year
  • Some cause disease in humans, animals and plants
  • Major cause of plant diseases