Science final exam - trimester 3 Flashcards
single-celled prokaryotic, microscopic organism
bacterium
two things missing from all prokaryotic cells
nucleus, organelles
why is bacteria DNA called “naked”
just floats in the cytoplasm, not protected by nucleus
three shapes of bacteria
- round
- rod
- spiral
four ways bacteria obtain nutrients and energy
- feed on dead organisms
- take nutrients from living organisms
- energy from sun
- energy from chemical reactions
aerobic bacteria need ___ to survive
oxygen
anaerobic bacteria do NOT need ___ to survive
oxygen
whiplike structure used to move bacteria
flagella
short hair-like structures on bacteria that help them stick to surfaces
pili
form of cell division that bacteria use to produce two genetically identical cells
fission
how long does fission take?
20 minutes
how bacteria attach to each other and combine their DNA
conjugation
forms when bacteria build a thick internal wall to protect themselves from heat or drought
endospore
group of prokaryotes that used to be grouped as bacteria, but aren’t anymore
archaeans
five characteristics of archaeans
- no nucleus
- no organelles
- YES cell wall
- circular chromosome
- live in extreme environments like hot springs and salt lakes
five ways bacteria are beneficial
bioremediation, digestion, food production, nitrogen fixation, decomposition
using bacteria to clean up environmental pollution like oil spills or uranium leaks
bioremediation
foods that are made using bacteria
soy sauce, yogurt, cheese, vinegar
when bacteria convert atmospheric nitrogen to a form that plants can use
nitrogen fixation
when bacteria break down dead organisms, helping organisms to grow
decomposition
anything that causes disease
pathogen
medicines that stop bacteria from growing or reproducing
antibiotic
two ways bacteria might enter the body
- inhale
- eat
two ways bacteria might cause infection
- damage tissue
- release toxins
steps in antibiotic resistance (bacteria become immune)
1) some bacteria naturally have a mutation that makes antibiotic resistance
2) treat the bacteria with an antibiotic, only the resistant bacteria survive
3) the resistant bacteria reproduce
heating food to a temperature that kills most harmful bacteria
pasteurization
the manner in which traits are passed from parents to offspring
heredity
a __ trait masks (or hides) another trait
dominant
a ___ is masked (or hidden) by another trait
recessive
father of genetics
Mendel
why pea plants were a great choice for Mendel’s experiments
- grow fast
- lots of simple traits
- can self-pollinate OR cross-pollinate
process by which one plant fertilizes itself or another plant, causing the production of offspring
pollination
plants with parents that look like them can be called ___-breeding plants
true-breeding
process by which one plant pollinates a DIFFERENT plant
cross-pollination
In Mendel’s first cross, he crossed true-breeding purple plants with true-breeding white plants. The offspring were…
all purple
In Mendel’s second cross, he self-pollinated the purple plants that were created by his first cross. The offspring were…
75% purple, 25% white
a gene travels on a long piece of DNA called a ___
chromosome
__ are different versions of genes. For example, there is one for purple plants and a different one for white plants
alleles
An organism’s __ is its physical appearance or trait
phenotype
An organism’s __ is the combination of alleles that it has for a particular trait. The combination can be heterozygous or homozygous
genotype
homozygous dominant genotype
AA
homozygous recessive genotype
aa
heterozygous genotype
Aa
type of chart that can be used to predict the types of offspring that parents will have
Punnett square
true/false: a virus is alive
false
two key parts of a virus
genetic material (DNA or RNA) surrounded by a protein coat (capsid)
Viruses cannot reproduce on their own. In order to reproduce, viruses require the help of a __ cell.
host
A(n) ___ virus is one that is not actively reproducing or harming its host
latent
A(n) ___ virus is one that is reproducing and is harming its host
active
Viral infections are difficult to treat because viruses are constantly __
mutating, changing
a protein produced by your body’s immune system that attacks bacteria and viruses
antibody
a small dose of a virus that prevents infection by introducing your body to the virus, so that your immune system recognizes it the next time you get sick
vaccine
