Unit 3 - microbiology, animals Flashcards
1st line of defense
skin (barrier against most pathogens)
tears, saliva, mucus (trap pathogens so they can be flushed from body)
stomach acid (kills pathogens we swallow before infection
cilia (microscopic hairs on cells that line airways
2nd line of defense
general response to infection
fever (high temp slows or kills some pathogens)
inflammation (more blood is directed to that part of body, blood has white blood cells that fight pathogens)
3rd line of defense
lymphocytes
antibodies
what are ways that you can catch a virus
insect bites, sneezing or coughing
what are the 2 parts in a virus
genome (DNA or RNA)
capsid (protein shell that protects the genome)
also have: proteins called receptors that stick out of the shell and an envelope (like a cell membrane)
what is the first step of a virus invading your body
get inside the cell
cells have sensors that are called receptors with shapes that fit the shapes of nutrients - when a matching receptor and nutrient locks, the cell puts them inside
viruses camouflaged to trick the cell
what is the second step of a virus invading your body
making more viruses
virus adds genome to the blueprint (the cell doesn’t know that the new blueprint is from the virus)
what are epithelial cells
millions of epithelial cells packed together line your skin, throat, intestines, blood vessels, etc
barrier between the enviornment and internal cells
what are macrophages
a white blood cells, the first types of cells at the infection. Epithelial cells release chemicals that attract macrophages to help treat the site of infection
what are neutrophils
most common type of white blood cell – first cells at site of infection
made in the bone marrow and travel through the bloodstream
what are t-cells
a type of white blood cell that works with macrophages, however unlike them they can only fight one type of virus
what is the lytic cycle
involves a virus taking control of a host cell, and uses it to make more copies of itself to take over and kill the cell.
When the cell is killed, the viruses leave the cell and take over more cells
(common cold - not as aggressive - symptoms are when cells get killed)
what is the lysogenic cycle
involves assimilating the genome with the host cell genome - this completes replication without killing the host cell
(symptoms not shown - asymptomatic)
what 6 characteristics are needed to be classified as a living thing
- responds to the environment
- grows and develops
- produces offspring
- maintains homeostasis
- complex chemistry
- consists of cells
what are the 3 different groups bacteria are arranged into to identify their shape
cocci (circular)
bacilli (cylinder)
spiral
what colour will a gram-positive bacteria stain be
purple
bacilli
what colour will a gram negative bacteria be
red
bacilli
what are the 2 ways bacteria receives their energy supply
- respiration - involves oxygen and breaks down food molecules to release energy
- fermentation - the breakdown of glucose and the release of energy without the need for oxygen
what are the 3 groups of bacteria
- obligate aerobes (require a constant supply of oxygen to live)
- obligate anaerobes (don’t require oxygen, can be killed in the presence of it)
- facultative anaerobes (can survive with or without it - e. coli)
what are the 4 phases of bacteria growth
- lag phase - longest (little to no cell growth while bacteria acclimatizes to environment - DNA replication occurs)
- log phase - exponential growth (doubling every few min)
- stationary - growth slows and cell death rate matches growth rate
- death - lots of waste produced and little food available
what the 3 ways bacteria reproduces
binary fission
conjugation
spore formation
what is binary fission
when the bacterium has doubled in size, then the DNA replicates itself and divides in half producing 2 identical daughter cells (asexual reproduction)
what is conjugation
form of sexual reproduction where the transfer of genetic material occurs through a long protein bridge that goes from one cell (donor) to another (recipient). DNA of the recipient is different now
what is spore formation
spores are produced when conditions are unfavorable. some produce endospores to protect the DNA. these can remain dormant for months and become active only when favorable.
(not technically reproduction, but makes it possible for bacteria to survive harsh conditions)
define autotroph
an organism that is capable of producing its own food from inorganic substances (thru photosynthesis)
define a heterotroph
an organism that cannot produce its own food and relies on consuming organic matter
