Bio test 2 flas

Characteristics of bacteria

All bacteria are single-celled prokaryotic organisms, reproduce asexually, and contain DNA made of a single chromosome.

Nitrogen fixation

Some bacteria convert nitrogen in the air into usable forms to make proteins, often living in nodules on legume roots.

Carbon-oxygen cycle

Bacteria play a key role in breaking down dead organisms and cycling carbon dioxide back into the atmosphere.

Production of vitamin K and B12

Occurs in humans in the large intestine, where bacteria help synthesize these essential vitamins.

Size of bacteria

Typically ranges from 1 to 10 micrometers (µm).

DNA in bacteria

DNA is not enclosed in a nucleus and is located loose in the cytoplasm.

Flagellum

A whip-like structure used for movement, not always present in bacteria.

Plasmid

A loop of DNA exchanged between bacteria during conjugation.

Cytoplasm in bacteria

Contains ribosomes for protein synthesis and serves as a 'factory' for protein production.

Capsule in bacteria

A protective layer that reduces water loss, resists high temperatures, and protects against antibiotics and viruses.

Cocci

A term used to describe round-shaped bacteria.

Bacilli

A term used to describe rod-shaped bacteria.

Spirilli

A term used to describe spiral-shaped bacteria.

Staphylo

A prefix indicating clusters of bacteria.

Strepto

A prefix indicating chains of bacteria.

Diplo

Indicates pairs of bacteria.

Mono

Refers to individual bacterial cells.

Naming bacteria

Typically involves a combination of the group and shape.

Gram-Positive

Bacteria that stain purple after a dyeing process, characterized by a thick cell wall.

Gram-Negative

Bacteria that stain pink, have a thin cell wall, and often include pathogenic strains.

Heterotrophic

Organisms that must consume other organisms for food.

Autotrophic

Organisms that can make their own food, including photoautotrophs (use sunlight) and chemoautotrophs (use chemicals).

Aerobic

Organisms that require oxygen to produce energy, can be obligate or facultative.

Anaerobic

Organisms that do not require oxygen to produce energy.

Binary fission

A method of asexual reproduction where a single bacterium divides into two identical cells.

Conjugation

A process where two bacterial cells connect and exchange genetic material under less-than-ideal conditions.

Effects of conjugation

Creates genetic variation and can lead to antibiotic resistance in bacteria.

Endospore formation

A survival mechanism that allows bacteria to withstand adverse conditions.

Endotoxins

Toxins produced inside bacteria that are released when Gram-negative bacteria divide.

Exotoxins

Toxins secreted by living bacteria, often fatal.

Are viruses alive?

No, because they are not composed of cells and cannot reproduce independently.

Characteristics of viruses

Viruses are parasitic, cannot live independently, and require host cells for replication.

Size of a virus

Typically ranges from 0.01 to 0.1 micrometers (µm).

Structure of a virus

Consists of a nucleic acid core, protein coat (capsid), and external proteins.

Nucleic acid core

Contains genetic material, which can be DNA or RNA.

Protein coat (capsid)

Externally protects the virus and determines its shape.

External proteins

Assist in virus recognition and attachment to host cells.

Bacteriophage

A virus that infects and replicates within bacteria.

Animal virus

A virus that can trigger host cells to ingest it through endocytosis.

Plant virus

Typically enters through cell wall injuries or during pollination.

Lytic cycle

A viral reproduction cycle that involves rapid replication and destruction of host cells.

Lysogenic cycle

A slower viral reproduction cycle where viral DNA integrates into the host cell's DNA.

Simple RNA viruses

Take over host cell functions directly and do not interact with host DNA.

Retrovirus

A virus that integrates its RNA into the host DNA, often leading to high mutation rates.

Cell lysis

The process where virus particles build up in a cell until it bursts open.

Exocytosis

A method by which viruses exit the cell without damaging its structure.

Virus transmission from animals to humans

Involves mutations that facilitate the jump and must evade the immune system.

Limiting new viral infections

Includes quarantine, mask-wearing, and avoiding sick animals.

Prions

Abnormally shaped proteins that cause brain degeneration in mammals.

Bovine spongiform encephalopathy (BSE)

A prion infection in cattle that can spread to humans through contaminated food.

CJD (Creutzfeldt-Jakob disease)

A prion disease causing rapid dementia and neurological problems.

Kuru

A prion disease spread through cannibalism, previously common in Papua New Guinea.

Viroids

Infectious RNA pieces that do not code for proteins and affect plants.

Parasites

Organisms that live on or in a host to obtain nutrients at the host's expense.

Helminths

Parasitic worms that infect humans through contaminated water or soil.

Protozoa

Single-celled organisms that can cause various human diseases, often transmitted by insects.

Malaria

A mosquito-borne disease caused by the Plasmodium parasite.

Toxoplasmosis

An infection caused by Toxoplasma gondii, often transmitted through infected food or cat feces.

Ectoparasites

Parasites that live on the external surface of hosts, such as lice and fleas.

Ticks

Ectoparasites that can transmit diseases like Lyme disease.

Fungi

Organisms that can cause infections such as athlete's foot and yeast infections.

Surface barriers: Skin

Prevents pathogen entry; consists of dead and living cells.

Surface barriers: Mucosa

Protects body openings and is lined with commensal bacteria.

Surface barriers: Tears

Wash away foreign materials and contain enzymes to kill bacteria.

Innate immune system functions

Identifies and removes foreign materials and recruits immune cells.

Cytokines

Molecules that send signals in the immune system.

Cells in the innate immune system

Include phagocytes, granulocytes, and natural killer cells.

Phagocyte cells

Include macrophages and neutrophils, crucial for engulfing pathogens.

Granulocytes

Cells that kill pathogens and regulate other immune cells.

Natural killer cells

Target and destroy compromised host cells without prior activation.

Adaptive immune system functions

Recognizes pathogens and creates immune memory.

T Cells

Immune cells that fight infections by injecting toxins or signaling cell death.

B Cells

Produce antibodies and play a crucial role in the immune response.

Where do T cells originate?

T cells develop in the thymus.

Memory T cells

Long-lasting cells that remember past infections and protect from re-infection.

Where do B cells originate?

B cells mature in the bone marrow without extensive training.

Antibody

Proteins produced by B cells that bind to antigens.

Antigen

A foreign molecule that triggers an immune response.

Lymphatic system

Network involved in transporting immune cells and removing excess fluid.

Thymus

Site of T cell maturation and training.

Bone marrow

Produces blood cells and immune cells.

Spleen

Filters blood and stores immune cells.

Infections benefits

The immune system helps fend off pathogens and tolerates good bacteria.

Wound repair benefits

Immune cells help heal injuries and regenerate tissue.

Cancer benefits

The immune system identifies and eliminates cancer cells.

Allergies harms

Immune reactions to harmless antigens can cause serious symptoms.

Autoimmune diseases

When the immune system mistakenly attacks its own tissues.

Immune deficiency

Inactivity of one or more components of the immune system.

Suppression effects

Factors like stress and lack of sleep impair immune function.

Boosting myths

Healthy individuals cannot significantly boost their immune system.

Avoiding colds/flu tips

Stay away from sick individuals and maintain hygiene practices.

3 benefits of bacteria

1. Nitrogen fixation, 2. Decomposition, 3. Vitamin production.

3 negative consequences of bacteria

1. Infections, 2. Endotoxins, 3. Exotoxins.

3 benefits of viruses

1. Medical applications, 2. Immunity training, 3. Driving evolution.

3 consequences of viruses

1. Diseases, 2. Genetic mutations, 3. Food source depletion.

Antibiotics

Medications that treat bacterial infections.

Vaccines

Inactivated pathogens that provide immunity against diseases.

Pandemic

A widespread occurrence of an infectious disease.

Epidemic

An outbreak of an infectious disease in a community.

Endemic

A disease regularly found in a specific area.