7th Science Bateria & Virus Outlines Flashcards
_______ are unicellular organism that do not have a nucleus or other membrane-bound organelles.
Prokaryotes
_______ are microscopic prokaryotes.
Bacteria
There are two types of prokaryotes - bacteria and ______.
Atchaea
A typical bacterium consists of DNA and ____ surrounded by a cell membrane and a cell wall.
cytoplasm
Bacterial cytoplasm also contain _______.
Ribosomes
Bacterial DNA occurs in one coiled, circular ________.
Chromosome
A bacterium might also have smaller, circular __________ that are separate from its other DNA.
Pieces
Many bacteria have capsules with hairlike structures called ________ that help the bacteria stick to surfaces.
Pili
Bacteria are much _______ than plant or animal cells.
Smaller
Bacteria generally have one of three basic shapes - sphere, rod, or ______.
Spiral
Some bacteria take in food and break it down and obtain _______. The food can come from dead organisms or ________ hosts.
Energy; living
Other bacteria make their food using energy from ______ or chemical reactions.
Light
________ bacteria can survive without oxygen.
Anaerobic
________ bacteria need oxygen, as humans do.
Aerobic
Many bacteria have long whiplike structures called _____ that they use for movement.
Flagella
Bacteria reproduce asexually by ________. This type of cell division forms two genetically _______ cells.
Fission; indentical
During _______, two bacteria of the same species attach to each other and combine their genetic material.
Conjugation
_______ is transferred between bacteria during conjugation.
DNA
Conjugation results in new combinations of genes and increases genetic ______.
Diversity
A(n) __________ forms when a bacterium builds a thick inner wall around its chromosome and part of the cytoplasm.
Endospores
An endospore can protect a bacterium from intense heat, cold, or ________. It can remain ________ for months or even centuries.
Drought; dormant
Like a bacterium, a(n) ________ has a cell wall but no nucleus or membrane-bound organelles.
Arachaea
The ribosomes of archaea more closely resemble the ribosomes of ________ than those of bacteria.
Eukaryotes
Archaea often live in _______ environments, such as hot springs and salt lakes.
Extreme
Many organisms, including humans, depend on ______ to survive.
Bacteria
Bacteria living inside the ______ of humans and other animals help digest food, make vitamin K, and prevent harmful bacteria from growing.
Intestines
Bacteria in the rumens of cows break down a substance in grass called _______ into smaller molecules that the cow can use.
Cellulose