Chapter 27

Question 1

What are the most common shapes of prokaryotics?

Answer 1

Spherical (Cocci), Rod-shaped

Bacilli), and Spiral (Spirilla

Question 2

What were the first organisms to inhabit earth?

Answer 2

Prokaryotics that lived 3.5 billion years ago.

Question 3

What is a key feature of nearly all prokaryotic cells?

Answer 3

The cell wall, which maintains cell shape, protects the cell, and prevents it from bursting in a hypotonic environment.

Question 4

What do the bacterial cell walls of prokaryotics contain?

Answer 4

Prokaryotic cells walls contain peptidoglycan a polymer composed of modified sugars cross-linked by short polypeptides.

Question 5

What is the gram stain technique?

Answer 5

Gram staining is a common technique used to differentiate two large groups of bacteria based on their different cell wall constituents. Gram positive bacteria stains violet due to the presence of a thick layer of peptidoglycan in their cell walls, which retains the crystal violet these cells are stained with.

Question 6

Why is Gram Staining an important medical tool?

Answer 6

It can quickly determine if a patients infection is due to gram-negative or gram-positive bacteria.

Question 7

The lipid portions of the lipopolysaccharides in the walls of many gram-negative bacteria are toxic causing what?

Answer 7

Fever or Shock

Question 8

Which is more resistant to antibiotics? Gram negative or postitive bacteria?

Answer 8

Gram-Negative bacteria because the outer membrane impedes entry of the drugs

Question 9

Can Gram-Positive bacteria be resistant to antibiotics?

Answer 9

Yes there are some forms that are.

Question 10

The cell wall of many prokaryotes is surrounded by what?

Answer 10

A sticky layer of polysaccharide or protein, This layer is called a capsule if it is dense and well-defined. or a slime layer if it is not well organised.

Question 11

What do stick layers of the prokaryotic cell wall enable prokaryotes to do?

Answer 11

Both kinds of sticky outer layers enable prokaryotes to adhere to their substrate or to other individuals in a colony. Some also protect against dehydration and some shield pathogenic prokaryotes from attacks by their host’s immune system.

Question 12

What are endospores?

Answer 12

a resistant asexual spore that develops inside some bacteria cells.

Question 13

When do certain bacteria develop endospore resistant cells?

Answer 13

When they lack water or essential nutrients

Question 14

How do endospores form?

Answer 14

When the original cell produces a copy of its chromosome it surrounds that copy with a multilayered structure, forming the endospore. Water is removed from the endospore and its metabolism halts, the cell then lyses releasing the endospore.

Question 15

How do you kill endospores?

Answer 15

They are very durable and can survive boiling water so killing them requires heating lab equipment to 121.c under high pressure.

Question 16

What are fimbriaes?

Answer 16

Hairlike protein containing appendages that allow some prokaryotes to attach to surfaces or to other cells.

Question 17

How does the bacteria that causes gonorrhoea use fimbriae?

Answer 17

It uses fimbriae to fasten itself to the mucous membranes of its host

Question 18

What are pili?

Answer 18

A pilus is a thin, rigid fiber made of protein that protrudes from the cell surface. The primary function of pili are to attach a bacterial cell to specific surfaces or to other cells (They pull two cells together prior to DNA transfer from one cell to the other)

Question 19

What is taxis?

Answer 19

The directional movement away or towards and stimulus

Question 20

What is the most common structure that enables prokaryotes to move?

Answer 20

Flagella

Question 21

What is flagella in the prokaryotic cell?

Answer 21

Flagella are primarily used for cell movement and are found in prokaryotes as well as some eukaryotes. The prokaryotic flagellum spins, creating forward movement by a corkscrew shaped filament. A prokaryote can have one or several flagella, localised to one pole or spread out around the cell.

Question 22

Are flagella analogous or homologous structures?

Answer 22

Analogous structures

Question 23

What are analogous structures?

Answer 23

Analogous structures are similar structures that evolved independently in two living organisms to serve the same purpose.

Question 24

What are homologous structures?

Answer 24

Homologous structures are organs or skeletal elements of animals and organisms that, by virtue of their similarity, suggest their connection to a common ancestor

Question 25

What is the bacterial flagellum?

Answer 25

Bacterial flagella are helically shaped structures containing the protein flagellin. Bacterial flagella are complex and well honed organelles that provide swimming and swarming motilities and also play a central role in adhesion, biofilm formation, and host invasion

Question 26

How many different types of proteins are the bacterial flagellum composed of?

Answer 26

42

Question 27

How did the bacterial flagellum evolve?

Answer 27

Evidence indicates that the bacterial flagellum originated as simpler structures that were modified in a step-wise fashion over time.

Question 28

How many of the flagellum’s proteins appear to be necessary for it to function?

Answer 28

Only half

Question 29

What is exaptation?

Answer 29

Where structures originally adapted for one function to take on new functions through descent with modification. For example, a trait can evolve because it served one particular function, but subsequently it may come to serve another.

Question 30

Which cells are more simple? Prokaryotic or eukaryotic?

Answer 30

Prokaryotic cells

Question 31

Do prokaryotic cells have specialised membranes?

Answer 31

Yes

Question 32

Where and what are the specialised membranes of prokaryotic cells?

Answer 32

They are usually infolding’s of the plasma membrane and recent discovery’s indicate that some prokaryotic’s can store metabolic by products in simple compartments that are made out of proteins, these compartments do not have a membrane.

Question 33

In most cases which cell has more DNA? Prokaryotic or eukaryotic cells?

Answer 33

Eukaryotic cells

Question 34

What type of chromosomes do prokaryotic cells tend to have?

Answer 34

Circular chromosomes.

Question 35

What type of chromosomes do eukaryotic cells tend to have?

Answer 35

Linear chromosomes

Question 36

Do prokaryotic have a nucleus?

Answer 36

no, their chromosome is located in the nucleoid

Question 37

What are plasmids?

Answer 37

A plasmid is a small, circular, double-stranded DNA molecule that is distinct from a cell’s chromosomal DNA. Plasmids naturally exist in bacterial cells

Question 38

Are ribosomes bigger in eukaryotic or prokaryotic cells?

Answer 38

Eukaryotic

Question 39

What is a benefit of the difference of the ribosomes of eukaryotic cells being bigger than the ribosomes of prokaryotic cells?

Answer 39

These differences allow certain antibiotics, such as erythromycin and tetracycline, to bind to ribosomes and block protein synthesis in prokaryotes but not in eukaryotes. As a result, people can use these antibiotics to kill or inhibit the growth of bacteria without harming themselves.

Question 40

What is binary fission?

Answer 40

In the process of binary fission, an organism duplicates its genetic material, or deoxyribonucleic acid (DNA), and then divides into two parts (cytokinesis), with each new organism receiving one copy of DNA.