Biology Chapter 4

Question 1

Explain how antibiotics specifically target bacteria while minimally harming the human host.

Answer 1

Antibiotics target bacteria while minimally harming the human host by binding structures only found in bacterial cells (bacterial ribosomes or particular enzymes)

Question 2

Compare light microscopes versus electron microscopes

Answer 2

Light microscopes use light passing through cells, Electron microscopes use a beam of electrons. Electron microscopes have 100x better resolution.

Question 3

Compare scanning electron microscopes versus transmission electron microscopes

Answer 3

• Scanning electron microscopes examine cell surfaces
• Transmission electron microscopes examine internal structure of cells.

Question 4

Compare magnification versus resolution

Answer 4

• Magnification is the number of times an image’s size is enlarged
• Resolution is how well the smallest details of an image can be discerned

Question 5

Compare prokaryotic cells versus eukaryotic cells

Answer 5

• Prokaryotic: Bacteria and Archaea (older, smaller, simpler)
• Eukaryotic: protists, plants, fungi, animals (newer, larger, more complex)

Question 6

Compare plant cells versus animal cells.

Answer 6

Plant cells:rigid cells, contain cell wall, vacuole, and chloroplast.

Animal cells: flexible, contains centriole and lysosome

Question 7

Describe the structure of the plasma membrane and other membranes of the cell. Explain why this structure is called a fluid mosaic.

Answer 7

Plasma membranes and other membraines of the cell is made of lipids and proteins. It is called a fluid mosaic because it contains a diversity of proteins (mosaic) that can move past one another freely (fluid).

Question 8

Explain how MRSA bacteria disable human immune cells.

Answer 8

MRSA uses a protein called PSM to rip holes in the plasma membranes of human immune cells.

Question 9

Compare the structures and functions of a plant cell wall and the extracellular matrix of an animal cell.

Answer 9

Plant cell wall: rigid walls made of cellulose that protect cell and keep it from absorbing too much water.

Extracellular matrix: holds cells together in tissues, and protects and supports cells.

Question 10

Explain how the genetic information in the nucleus is used to direct the production of proteins in the cytoplasm.

Answer 10

DNA is transferred to mRNA (messenger RNA), which exits the nucleus through pores in the nuclear envelope. A ribosome moves along the RNA, which translates the genetic message into a protein.

Question 11

rough endoplasmic reticulum

Answer 11

Ribosomes that stud theoutside of the ER membrane, produce membrane proteins and secretory proteins.

Question 12

smooth endoplasmic reticulum

Answer 12

Smooth endoplasmic reticulum has no surface ribosomes, and it produces lipids (including steroids) and helps liver cells detoxify circulating drugs.

Question 13

Golgi apparatus

Answer 13

The Golgi apparatus works with the ER (Endoplasmic Reticulum) and receives, refines, stores, and distributes chemical products of the cell.

Question 14

Lysosome

Answer 14

A lysosome is a sac of digestive enzymes that breaks down large molecules like: Proteins, polysaccharides, fats, and nucleic acids.

Question 15

Vacuole

Answer 15

Large sacs of membrane that pump excess water from the cell

Question 16

Compare the structure and function of chloroplasts and mitochondria.

Answer 16

Chloroplasts: exist only in plant cells, convert light to energy through photosynthesis. They are divided into three sections by internal membranes.

Mitochondria exist in almost all eukaryotic cells, perform cellular respiration and convert food molecules to ATP. They are an envelope with two membranes.

Question 17

Describe the adaptive advantages of extensive folds in the grana of chloroplasts and the inner membrane of mitochondria.

Answer 17

The folds in the grana of chloroplasts and the inner membrane of mitochondria hold DNA so they can encode some of their own proteins.

Question 18

Describe the functions of the cytoskeleton.

Answer 18

Cytoskeleton provides mechanical support to the cell and helps it maintain its shape.

Question 19

Compare the structures and functions of cilia and flagella.

Answer 19

Both Cilia and Flagella help cells move

Cilia move in a coordinated back and forth motion

Flagella move in a whiplike motion

Question 20

Explain how and why antibiotic-resistant bacteria have evolved.

Answer 20

The widespread use and abuse of antibiotics ensure that bacteria that are resistant to antibiotics survive and multiply while less resistant bacteria are destroyed.