Similarities, Controversies, and Bacterial Cellular Components Homework

Homework Questions Identify all the general similarities between Bacteria and Archaea. - Lack membrane-bound organelles Lack membrane-bound nucleus Historically, prokaryotes were differentiated from eukaryotes by ______. - The absence of a nucleus Which of the following describes the controversy concerning the use of the term "prokaryote?" - Biochemical, genetic, and genomic analysis have shown that Bacteria and Archaea are distinct taxa. Which genus gets its name due to the cellular arrangement of spherical cells found in clusters, like a bunch of grapes? - Staphylococcus Match the following common bacterial cellular components with their function. - Cell wall - protection against osmotic stress Cell membrane - selectively permeable barrier Capsule - protective layer and sometimes aids in adhesion Ribosomes - site of protein synthesis Which of the following shares a basic body plan with bacteria? - Archaea What term is used to describe the plasma membrane and all layers external to it? - Cell envelope Prokaryotes were not fully described until 1962 when scientist grouped them together based on ___________. - what they lacked compared to eukaryotes Which of the following terms describes the way in which lipids and proteins behave in a membrane? - Fluid mosaic model Which of the following organisms appears to blur the lines between prokaryotes and eukaryotes? - Archaea Which term describes the cellular arrangement of spherical cells linked in a chain? - Streptococcus Plasma membranes are organized by having ______. - two lipid layers Which of the following cellular components are commonly found in most bacterial cells? - Ribosomes Capsule Flagella Cell wall Slime layer The _____ is defined as the plasma membrane and all surrounding layers external to it (e.g., cell wall and/or capsule). - Cell envelope Bacteria growing at higher temperatures have phospholipids with _____. - more saturated fatty acids Drs. Singer and Nicholson proposed a model to describe how lipids behave in a membrane called the - Fluid mosaic model Which describes a bacterial hopanoid? - Sterol-like compounds How many lipid layers are found in a bacterial plasma membrane? (Note: a lipid layer consists of a series of phospholipids arranged side to side with hydrophilic heads all facing one direction and hydrophobic tails facing the other direction) - Two Which of the following is true regarding macronutrients and micronutrients? - Macronutrients are substances needed in large quantities. The lipid composition of a plasma membrane varies with the environmental temperature. The structural changes to the phospholipids occurs in the _____ - Hydrocarbon chains Bacterial plasma membranes contain ____, rigid planar lipids similar to cholesterol found in eukaryotic cell membranes. - Hopanoids Macroelements include which of the following? - Carbon, sulfur, oxygen, hydrogen and a few others Elements required in low concentrations for cell growth are called ______. - Micronutrients Compounds such as essential amino acids are considered _____. - Growth factors Compounds considered to be growth factors ______. - are acquired from the environment Zinc, cobalt, molybdenum, nickel, and copper are examples of ______. - Micronutrients Which three of the following are growth factors? - Vitamins Some amino acids Some nucleotides Which of the following transport mechanisms relies on concentration gradients of one substance to power the translocation of a different substance across a membrane? - Secondary active transport The lipid composition of a plasma membrane varies with the environmental temperature. The structural changes to the phospholipids occurs in the _____ - Hydrocarbon chains True or false: Bacterial cells uptake nutrients that are dissolved. - True Compounds that must be acquired from the environment for cell survival are called _______. - Growth factors Which of the transport mechanisms relies only on concentration gradients to provide the "force" to move materials across the plasma membrane? - Passive diffusion Molecules crossing a plasma membrane from a ____ concentration to a ____ concentration without energy use is an example of passive diffusion. - High/low Bacterial cells acquire nutrients that are ____. - Dissolved Zinc, cobalt, molybdenum, nickel, and copper are examples of ______. - Micronutrients Substances like oxygen, carbon dioxide and water move across a bacterial cell membrane by _____. - Passive diffusion Which of the following transport mechanisms relies on concentration gradients of one substance to power the translocation of a different substance across a membrane? - Secondary active transport The "energy-free" movement of molecules across a membrane with the aid of a transporting protein is called ______. - facilitated diffusion A cell is placed into a slightly hostile environment where the temperature is not ideal for the cell but tolerable. Which of the following transport mechanisms would probably work the fastest? - Passive diffusion because it is unaffected by the hostile conditions Proteins characterized as channels and carriers are ______. - Transport proteins Which three of the following substances cross a membrane by passive diffusion? - Water Oxygen Carbon dioxide Which of the transport mechanisms relies only on concentration gradients to provide the "force" to move materials across the plasma membrane? - Passive diffusion As you add more and more solute, facilitated diffusion by carriers will __________. - reach a maximum rate of transport Which of the following describes proteins that aid in the movement of materials across a membrane? - Channels and carriers Substances like oxygen, carbon dioxide and water move across a bacterial cell membrane by _____. - Passive diffusion A carrier protein that transports solute molecules by facilitated diffusion has _____ configuration(s) because _____. - two; it needs to bind solute outside the cell and then release it in the cytoplasm When facilitated diffusion reaches a maximum rate (arrow), this indicates that ____. - carrier molecules have been saturated by solutes Which of the following statements regarding carrier-mediated facilitated diffusion is false? - The carrier protein moves solute molecules against a concentration gradient. As you add more and more solute, facilitated diffusion by carriers will __________. - reach a maximum rate of transport The use of ATP to power the movement of substance across a membrane is commonly referred to as ____ transport. - Primary active Active transport and facilitated diffusion are similar because they both ____. - use proteins to move materials across a membrane If the concentration of solute drops, what happens to facilitated - It slows down In active transport, the "active" refers to ____. - the use of energy to power the movement of molecules across a membrane