1.3 Bacteria And Viruses Flashcards
Know the Structure of a typical bacterial cell and typical virus Know the requirements for bacterial growth Know how bacteria reproduce Understand some ways bacteria and viruses affect human activities Understand why viruses don't fit into the five kingdoms of living organisms
bacteria
single-celled organisms
no true nucleus no organelles (unlike plant/animal cells)
some photosynthesise
most are parasites
some are saprotrophs
parasites
feed off living organisms
saprotrophs
feed off dead organisms
size of bacteria
1-2 micrometres
cocci (singular coccus)
spherical bacteria
bacilli (singular bacillus)
rod-shaped bacteria
spirilli (singular spirillum)
spiral bacteria
bacteria cytoplasm
contains enzymes, food molecules
no organelles
bacteria glycogen grains
food store
slime coat
present in some bacteria
bacteria cell wall
no cellulose
bacteria plasmids
small DNA rings, carry only a few genes
bacteria main DNA strand
not in a nucleus
bacteria flagella (singular flagellum)
one or several beat to move bacterium
parts of bacterial cell
slime coat (only some) cell wall cell membrane flagella cytoplasm (no organelles) glycogen grains plasmids main DNA strand
binary fission
cells divide into two repeatedly to reproduce
generation time
time for each cell to divide into two
pathogenic bacteria
cause disease
all are parasites
importance of bacteria
pathogenic
involved in nutrient cycles
used for food production, biotechnology
viruses
don’t show typical living characteristics unless inside other living cells - i.e. parasite
harm hosts
typical virus structure
spikes (contact & recognize cell to be infected) protein coat (protects nucleic acid. many subunits) genetic material (DNA/RNA - single strand only)
virus vs bacteria
covered by: protein coat // cell wall
cell membrane: no // yes
cytoplasm: no // yes
genetic material: DNA or RNA - only a few // DNA - enough for several hundred genes
living or non-living: not unless in host // living
nutrition: all are parasitic // parasite, photosynthesis, heterotrophs (like animals)