Introduction to Cell Size Study Question 6

List two reasons why it is it important for cells to maintain a large surface area to volume ratio?

- Cells require a large surface area for efficient movement of required materials to be moved into the cell and waste materials to be removed from the cell - Cells require a small volume in order to efficiently move materials to all parts of the cells cytoplasm

This is an electron micrograph of a bacterial cell isolated from the surface of stones in a stream. What is the name and function of the structures labeled by the arrow?

- Fimbriae or pili (1/4 pt.) - Attach cells to a surface (substrate)

Which of the following are TRUE statements about True Bacteria? Select all that apply.

- there are species of autotrophic and heterotrophic true bacteria -all true bacteria possess both DNA and RNA

Explain why initially, at the start of the bloom, the oxygen concentration in the water increased greatly.

-As the population of cyanobacteria increases there would be an increase in photosynthesis - Since oxygen is a by-product of photosynthesis, there would be an increase in the oxygen dissolved in the water.

Which of the following are true statements about methanogens? Check all that apply.

-possess a cell wall -produce a gas responsible for global warming -they belong to the Domain Archaeae -produce methane gas -they are single celled organisms -occur in large numbers in the digestive tracts of vertebrate animals - they are prokaryotes -possess ribosomes -they often live in habitats having low or no oxygen

Which labeled structure precisely regulates what materials enter and leave the cell?

1

Which two numbered structures contain DNA?

5 and 8

Antibiotics such as penicillin kill bacterial cells by inhibiting the formation of which labeled structure?

7

Which labeled structure often possesses genes which confer resistance to antibiotics to the bacterium?

8

List two ways the Rhozobium bacteria benefit from living in the environment inside the root tissue.

Stable temperature Moist environmentPhysical protection of the bacteria

How does the soybean plant benefit from having the Rhizobium bacterium carry out nitrogen fixation in its root tissue?

The nitrogen compounds produced during nitrogen fixation by the Rhizobiumbacteria in the root tissue (1/4 pt.) are transported to the plants tissue where they are used to make proteins and nucleic acids (1/4 pt.) required by the plant

Name the structures within a cyanobacterium cell on which or in which the biochemical reactions of photosynthesis take place.

Thylakoid membranes; no credit for thylakoids since thylakoids are membrane bound sacs in eukaryotic chloroplasts.

Label #4 represents the _______ of the cell. Spelling must be correct to receive credit.

cytoplasm

The video above shows several cells of the bacterium in human blood which causes Lyme Disease. In one sentence name the structures and their location which are responsible for the movement of these bacteria.

flexible rods (internal flagella) (1/4 pt.) lying between the cell wall and the cell the cell membrane.

What is the function of the structures labeled #2?

function of ribosomes= synthesis of proteins

As you increase the diameter of a white blood cell, the surface area of the blood cell ________ and the surface area to volume ratio of the red blood cell _______

increases; decreases

Based only on the structures visible in this diagram, explain why or why not this bacterium is most likely motile or non-motile.

it is most likely non-motile since no structure for movement (e.g. prokaryotic flagellum) is visible

Cyanobacteria carry out photosynthesis with the release of oxygen, the same process that occurs in plants. However, photosynthesis in cyanobacteria occurs in or on the _________ membranes in the cytoplasm whereas photosynthesis in plant cells occurs in or on membranes inside the organelles called

thylakoid; chloroplasts

Give one important function of the non-disease causing strain of E. coli which normally lives as a symbiont in the intestine of most vertebrates, including humans.

-aid in the digestion (metabolism) of food in the digestive tract - production vitamins which can be utilised by humans

Which of the following are true statements about cyanobacteria? Select all that apply.

-most species of cyanobacteria live in freshwater or marine habitats -cyanobacteria release oxygen as a by-product of photosynthesis -some species of cyanobacteria produce neurotoxins that can kill vertebrates if ingested -cyanobacteria cells possess a cell wall lying to the outside of the cell membrane

Which of the following are FALSE statements about Lyme disease? Check all that apply.

-the bacterium causing Lyme disease can be transmitted from person to person through the air, i.e. it is an air borne - the lyme disease bacterium produces a strong toxin which destroys the blood vessels within the human intestine - the bacterium causing Lyme disease is transmitted to humans via the saliva of Anopheles mosquito - if left untreated Lyme disease often leads to kidney failure and death

The diagram below represents a diagram of the bacterium Mycobacterium tuberculosis which causes the highly virulent disease tuberculosis. Answer questions #10- 18 based on this diagram. Which label represents a plasmid?

8

What is a bloom of the cyanobacterium?

Bloom of cyanobacteria = large amount of growth

In this experiment why were both test tubes containing Anabaena placed in the light?

Cyanobacteria require light to synthesize their organic compounds (sugars first) by the process of photosynthesis.

Although E. coli 0157 is naturally found living in the digestive tract of cattle, explain how humans often develop cases of E. coli food poisoning by eating spinach, lettuce or other leaf vegetables.

The leafy vegetables become cross contaminated with cattle feces containing E. coli 0157 by various ways including: run-off from feed lots, use of cow feces as fertilizer, irrigation water contaminated with cow feces

A human red blood cell, an E. coli cell, and an Anabaena cell (species of cyanobacterium) are all placed in distilled water. Although water enters each of these cells very rapidly, only the E. coli cell and the Anabaena cell do not burst. In no more than 3 sentences, explain why the red blood cell bursts but the E. coli and Anabaena cells do not.

when water rapidly enters a red blood cell it bursts since it doesn't have a cell wall whereas the prokaryotic cells (the true bacterium E. coli and the cyanobacterium Anabaena possess a cell wall which prevents the cells from bursting.

What is the importance of the process of conjugation in true bacteria? Be sure to provide a definition of conjugation.

Bacteria conjugation = exchange of DNA (usually one way) between bacterial cells

The nitrogen compounds produced by the Rhizobium bacteria as a result of nitrogen fixation can then be combined with monosaccharide sugars to synthesize the monomers of proteins called _________ and the monomers of nucleic acids called _________.

amino acids; nucleotides

What is the name of the structure labeled #6? Spelling must be correct to receive credit.

capsule

During the process of nitrogen fixation, the Rhizobium bacteria living in the root tissue convert ___________ gas from the atmosphere into __________ which is then converted into useable nitrogen compounds such as nitrates and nitrites.

nitrogen; ammonia

What is the source of the monosaccharide sugars used by the Rhizobium bacteria to (1) synthesize their protein and nucleic acid monomers and (2) used as an energy source to carry out their life processes?

plant photosynthesis produces the monosaccharides used by the bacteria to make their proteins, nucleic acids and ATP.

At the end of the 30 day period, the Anabaena posessing heterocysts showed a statistically significant higher growth rate than the Anabaena without heterocysts. In detail, explain these results.

- Both culture tubes of Anabaena contain no useable nitrogen compounds. - The heterocysts of cyanobacteria are the cells in which nitrogen fixation takes place. - During the process of nitrogen fixation, nitrogen gas dissolved in the water is converted into ammonia and then useable nitrogen compounds such as nitrates. -These useable nitrogen compounds are then used by the cyanobacteria to synthesize nitrogen containing compounds such as amino acids (the monomers of proteins) and nucleotides (the monomers of nucleic acids. As a result these organisms remain healthy and grow. - Those Anabaena filaments not having heterocysts and no other source for nitrogen compounds are nitrogen deficient and will grow very slowly if at all.

Explain why after about 15 days the oxygen concentration began to decline significantly and resulted in the death of a large number of fish.

- dead cyanobacterial cells sink to the bottom of the lake - Heterotrophic aerobic bacteria and other microorganisms take up "Feed on" the organic compounds (carbohydrates, proteins, etc.) available in the dead cyanobacteria cells during the process of decomposition. - The energy in these organic materials is converted into ATP during the process of aerobic respiration. The ATP is used by the bacteria to carry out their life processes. - Since the aerobic bacteria and other microorganisms consume oxygen from the water during aerobic respiration the concentration of oxygen in the water decreases.

E. coli is a common true bacterium. Answer questions #7 - 9 based on your knowledge of this organism. Which of the following are true statements about E. coli 0157? Check all that apply.

- it possesses flagella -it secretes a toxin which can destroy the blood vessels in the kidney; resulting in kidney failure - it possesses a slightly different genetic make-up than the non-disease causing strain of E. coli living in the intestines of humans

Which of the following are true statements about Salmonella enteriditis, the bacterium that causes salmonellosis food poisoning? Check all that apply.

-one common method is transmission of the bacterium to humans is eating insuffiently cooked chicken eggs infected with the bacterium. - the bacterium is generally transmitted to humans by eating improperly cooked foods which are contaminated with animal feces containing the bacterium -the bacterium causing salmonelloisis contains ribosomes in its cytoplasm

The temperatures of the water coming out of these vents often reach as high as 100 oC which is the upper temperature threshold for known life to exist. The cells of this organism are round in shape. Its optimum pH for growth is a pH of 9. They live at great depths in the ocean where light is absent.Hydrothermal vent communities include a variety of eukaryotic worms and clams. These animals depend on the archeae for their source of organic compounds (e.g. carbohydrates, lipids, proteins, etc.). These archeae synthesize their own organic compounds by using sulfur compounds, particularly hydrogen sulfide. Which of the following describe the cells of the Archean Pyrolobus fumari? Check all that apply.

-possesses ribosomes -autotrophic -possesses a cell wall -possesses a cell membrane -thermophyllic -chemoautotroph -possess DNA

What is the difference between the nucleoid region of a prokaryotic cell and the nucleus of a eukaryotic cell?

The nucleoid region of a prokaryotic cell is the region in the cytoplasm where the DNA (bacterial chromosome) is located (1/4 pt.) whereas the nucleus of a eukaryotic cell is a membrane bound organelle which contains the DNA (eukaryotic chromosomes) (1/4 pt.)

List 2 reasons (other than a decrease in oxygen concentration in the water) why during a bloom of the cyanobacterium Microcystis can result in fish kills.

Two reasons other than decrease in oxygen concentration for fish kills during bloom of cyanobacteria such as Microcystis - Gills of the fish get physically clogged with cyanobacteria, resulting in less than optimum oxygen being transported to tissues of fish - A number of species of cyanobacteria including Microcystis produce neurotoxins which can kill the fish.