Name: ________________________________________________ Date: ______________

Unit 8 – Microbiology – Guided Notes

Bacteria

The most plentiful organism on the planet is microscopic,

____________________. They are made of ____ cell and are the ____________________

form of life on Earth. Most are helpful to humans, they ____________________,

____________________, and ____________________ for us. However, approximately

____% are harmful. These may ____________________ or ____________________.

Most bacteria have similar structures. In terms of membranes, many

have a cell ____________________, cell ____________________, and most will also have a

third layer known as the ____________________. The only internal structures,

besides the cytoplasm, are the ____________________ (used to make protein) and

the ____________________, the location of the genetic material. Finally, on the

outside of the cell, some bacteria may have ____________________ to help move and

____________________ to help attach to surfaces.

In terms of oxygen usage, bacteria fall into three categories. Those that

must use oxygen are known as ____________________ ____________________. Similarly,

those that cannot use oxygen are known as ____________________

____________________. Some, however, can survive with or without oxygen; these

are known as ____________________ ____________________.

Bacteria typically take one of three shapes. Rod-shaped bacteria are

described as ____________________. Spherical bacteria are ____________________.

Those bacteria with curved cell shapes are known as ____________________.

Bacteria reproduce by ____________________ ____________________, a basic

process of cell division. Though not truly reproduction, sometimes they may

exchange genetic material by the process of ____________________. In unfavorable

conditions, bacteria will create an ____________________ to help survive until the

environment is more favorable to them.

For the 1% of bacteria that do cause harm, two main types of treatments

are available. ____________________ are dead or weakened forms of bacteria that

help boost the immune response. On the other hand, ____________________ are

drugs that disrupt the cellular processes of bacteria, but they come with the

risk of the bacteria developing ____________________ to the drugs.

Viruses

Besides bacteria, the other microscopic biological threat to humans may

come in the form of ____________________. Though not technically considered

alive, ____________________ do have a protein coat known as a ____________________

and some form of ____________________ ____________________.

There are many kinds of viruses out there. Those that attack bacteria

are known as ____________________. Those that attack animal cells are called

____________________ ____________________. Lastly, some of those that have RNA and

must use ____________________ ____________________ to convert it to DNA for use by a

host cell are called ____________________.

Reproduction by viruses takes one of two forms. The more destructive

form of reproduction is the ____________________ cycle, wherein phage DNA (DNA

from the virus) is immediately transcribed into RNA and used by the ribosome

to make new copies of the virus. The cell bursts, releasing the new virus

copies and is destroyed.

During the ____________________ cycle, done by many ____________________ and

some other viruses, involves bacterial DNA becoming a part of the cell’s

normal DNA. Later on, well after the initial infection, that section of DNA may

“turn on,” resulting in the production of the virus and symptoms similar to the

lytic cycle.

Notably, because they do not respire on their own and often use host

cells to reproduce, viruses cannot be treated with ____________________.