Understanding the Microbial World

How many cells approximately make up the human body?

• 37 million

• 37 billion

• 37 trillion

• 37 thousand

What is the main difference between prokaryotes and eukaryotes?

• Eukaryotes do not have DNA.

• Prokaryotes do not have a defined nucleus.

• Eukaryotes lack genetic material.

• Prokaryotes have a defined nucleus.

What unique genetic feature do most bacteria have?

• Multiple chromosomes

• A single, circular chromosome

• No chromosomes

• Two nuclei

What role do plasmids play in bacterial cells?

• They prevent gene transfer.

• They are essential for cell survival.

• They duplicate independently of the main chromosome.

• They are the main source of genetic material.

How does horizontal gene transfer benefit bacteria?

• It increases susceptibility to antibiotics.

• It decreases genetic diversity.

• It adds genetic diversity and new capabilities.

• It prevents new abilities.

What was a significant medical application of plasmid research in the 1980s?

• Curing genetic diseases

• Producing insulin from E. coli

• Developing a new type of antibiotic

• Creating synthetic blood

What does gene expression allow cells to do?

• Produce a single type of protein

• Eliminate all mutations

• Turn genes off and on as needed

• Replicate indefinitely

What determines the species a strain of Streptococcus can infect?

• The type of proteins expressed

• The size of the bacterial cell

• The carbohydrates on its surface

• Its resistance to antibiotics

How did Dr. Rebecca Lansfield contribute to our understanding of bacteria?

• By discovering the structure of DNA

• By creating the first vaccine

• By classifying bacteria based on antigens

• By inventing antibiotics

Why is Earth considered a microbial planet?

• Because bacteria can be found everywhere

• Because humans have colonized it

• Because it is covered in water

• Because life began with microbes