nats 1

Cell

The basic unit of life, composed of various structures that perform specific functions.

Unicellular

Organisms composed of a single cell, such as bacteria and yeast.

Multicellular

Organisms composed of multiple interdependent cells, such as plants and animals.

DNA

The molecule that contains the genetic information of organisms, utilized by all living things.

Central Dogma

The process by which DNA is transcribed into RNA and translated into proteins.

Plasma Membrane

A flexible barrier surrounding cells, regulating the passage of materials in and out.

ATP

Adenosine triphosphate; the primary energy currency used by cells.

Prokaryotic Cells

Simple cells that lack a nucleus and organelles; examples include bacteria.

Eukaryotic Cells

Complex cells containing a nucleus and membrane-bound organelles, found in organisms like humans.

Psychrophiles

Microorganisms that thrive at low temperatures. (0c)

Thermophiles

Microorganisms that thrive at high temperatures. (50c-80c)

Bacterial Resistance

The ability of bacteria to withstand the effects of antibiotics, posing a significant public health challenge.

Endocytosis

The process by which cells engulf substances from their external environment into vesicles.

Exocytosis

The process by which cells expel materials contained in vesicles to the exterior.

Antibiotics

Medications used to treat bacterial infections by killing or inhibiting bacterial growth.

Bioterrorism

The deliberate release of viruses, bacteria, or other germs to cause illness or death.

Emerging Infectious Diseases

Newly identified diseases or pathogens that are increasing in incidence or geographical range.

Mitochondria

Organelles that generate ATP, acting as the powerhouses of the cell.

Vesicle

Membrane-bound sac within a cell that transports materials.

Glycoproteins

Proteins that have sugars attached, playing roles in cell recognition and interaction.

Microbial Diversity

The variety and variability of microbial species in different environments.

unity of life

all living organisms, whether bacteria or humans share a fundamental characteristic: they are made of cells

cell composition

organisms can be made of a few billion cells that work collaboratively to promote growth and survival

genetic material

all organisms contain DNA as their genetic material showing sameness across species. this highlights biochemical machinery in biological information flow

genetic similarity

mammals share 97% of their genes with 3% differences between species. This shows that all living things are connected

phenotype

an observable characteristic or an organism, which are shaped by the protein it produces.

mesophiles

microbes that prefer moderate temperatures (20c-40c)

red blood cell (RBC)

is a type of human cell that doesn’t contain a nucleus

lymphocytes

are responsible for the immune system

acidophiles

microbes that thrive in acidic environments (ex. human stomach pH1-2)

neutrophiles

microbes that thrive in neutral environments (ex. bone marrow pH7)

alkaophiles

microbes that grow in basic environments (alkaline)

spores

are highly resistant and can remain dormant for extended periods

when water is available

spores can reactivate and turn into a vegetative state

aerobes

microbes that require oxygen for growth and metabolism

anaerobes

microbes that does not require oxygen to grow

cynaobacteria

were the first microbes to produce oxygen as a byproduct of photosynthesis

anaerobic prokaryotic cells

evolved into aerobic cells that can live in O2

amoebas

were among the earliest eukaryotic organisms on earth

methane producing microbes

the microbes convert CO2 into methane which is used as energy source

an example of a methane rich environment

swamps, wetlands

the importance of microbes

microbes maintain the balance of the biosphere, acting as recyclers and decomposers.

eukaryotic microbes

are diverse and plays an important role in various industries and ecosystem (ex. yeast, fungi)

protozoa

are unicellular eukaryotic organisms that lacks a cell wall

protozoas play a role

in various ecosystems (ex. the digestive system of ruminant animals and in the treatment of wastewater)

bacterial cells

are a primary food source of protozoa (ex. tetrahymena cells)

protozoa helps

remove waste water

tetrahymena protozoa cells

can be seen exchanging genetic information

viruses

are complexes of nucleic acid (DNA or RNA) and proteins and they can infect a wide variety of cells (including plant, human & bacterial cells)

viruses that infect bacteria

are called bacteriophages, which helps regulate the population of bacterial cells

bacteriophage infection

1. the bacteriophage recognizes and attaches to the surface of the bacterial cell

2. the bacteriophage injects its genetic material into the bacterial cell

3. the bacteriophage takes over the cells machinery to produce new virus particles

viruses often have

a protein coat to protect their genetic material and help them infect cells (some have lipid envelopes)

hydrophobic molecules

the structure of phospholipids is responsible for the basic function of membranes as barriers between two water compartments (ex. water & oil cannot mix) doesnt like water

cell membrane

• separates the inside of the cell from the outside

• provides a surface on which chemical reactions occur

• regulate the passage of materials in/out of the cell

the plasma membrane a flexible barrier

bilayers of the naturally occurring phospholipids are flexible jelly like fluids, not solids

transmembrane proteins

• cell to cell recognition

• signal transduction

passive diffusion

is where molecules move down the concentration gradient without energy

facilitated diffusion

requires channel proteins that allow specific molecules to cross the membrane based on size

carrier proteins

requires interactions with specific molecules, transport materials like glucose across the membrane without energy

active transport

mechanisms like the sodium potassium pump, move ions against the concentration gradient and require ATP for energy

sodium potassium pumps

works by binding sodium ions, followed by ATP hydrolysis that changes the pump conformation allows the release of sodium outside the cell while bringing the potassium in

glycolysis and ATP synthesis

gycolysis involves active transport establishing a concentration gradient of hydrogen ions, then drive passive transport in ATP synthesis

the creation of hydrogen concentration

is energy dependent while subsequent synthesis of ATP from the gradient does not require additional energy

vesicular transport

vesicle membrane pockets that carry molecules into or out of cells, bypassing direct membrane

endocytosis

enables cells to engulf substances, categorizing into phagocytosis for solid particles & pinocytosis for liquids.

receptor mediated endocytosis

involves specific receptor recognition of substances to facilitate entry

exocytosis

is the reverse process, discharging material from vesicle to the exterior of the cell, cruical for numerous cellular functions

during immune responses

phagocytes like macrophage can engulf pathogens through receptor mediated endocytosis. improving the recognition through binding to antibodies

mitochondria facilitate

ATP production through cellular respiration, crucial for energy metabolism

mitochondria contains

their own ribosomes, pposing.a risk affecting mitochondrial ribosomes

mitochondria

has a unique structure with 2 membranes & they are prokaryotic organisms that entered a larger host cell

endosymbiosis theory

is that eukaryotic cell evolved from a predatory prokaryotic cell engulfing an aerobic bacterium, leading to dependency

functions of the mitochondria

• production of ATP through oxidative phosphorylation, utilising proton gradients

• they regulate metabolic activities. surface area for biochemical reactions, enhancing ATP production

nucleus

• is the largest organelle, containing DNA organized into chromosomes, involved in gene expression regulation.

• a double membrane structure with nuclear pores that allow selective passage of molecules like RNA & proteins

endomembrane system consists of

the endoplasmic reticulum (ER), golgi apparatus, vesicle

the endomembrane system

is the system of protein synthesis, modification & transport

the rough ER

hosts ribosomes for protein synthesis

the smooth ER

is involved in lipid metabolism

protein sysnthesis in the ER

are transferred to the golgi apparatus for modification

golgi apparatus

is the sites protein modification & sorting station, packaging them into vesicle and is transported out

lysosomes

are membrane bounded organelles containing hydrolytic enzymes for digesting cellular materials and old organelles

lysosomes are involved in

programmed cell death, recycling of cellular materials & disposing waste

current major infectious diseases

HIV, AIDS, tuberculosis, malaria

roles of microbes in human life

digestion, immune system development and health

microbial contributions to ecosystems

• microbes are essential for nutrient recycling, food production & maintaining the ecological balance

• breakdown of waste & production of oxygen in the environment

historical impacts of pathogens

small pox, spanish influenza, bubonic plague (loss of life)

key improvements in public health

• handwashing

• development of vaccines

• introduction to antibiotics

remaining challenges with infectious diseases

• poor sanitary conditions

• the rise of antibiotic resistant bacteria

• new pathogens (HIV, coronavirus)

global spread of infectious disease

• rapid global movement of people by air travel facilitated the transmission of virus across countries

• modern transportation methods like planes, increase the potential of spread

emerging infectious diseases & bioterrorism

bioterrorism involves the intentional release of pathogens like bacteria, viruses or toxins

emerging disease factors

• microbial adaptation, human behavior & changing ecosystems by climate change

• global travel & environmental changes localizes the disease

mechanisms of resistance development

bacteria can mutate fast, developing resistance to antibiotics through acquiring genes that code for resistance