Unit 1 Section 2 Medium

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Questions and Answers

Which of the following structures is unique to eukaryotic cells?

Plasma membrane

Circular DNA

Ribosomes

Mitochondria (correct)

What is the primary method of reproduction in bacteria?

Binary fission (correct)

Budding

Meiosis

Fragmentation

Which term best describes bacteria that can vary in size and shape?

Bacillus

Coccus

Monomorphic

Pleomorphic (correct)

What is the primary function of the glycocalyx in bacteria?

Protection and attachment Signup and view all the answers

Which arrangement of flagella refers to a single flagellum at one pole of the cell?

Monotrichous Signup and view all the answers

What is a key structural difference between Gram-positive and Gram-negative bacteria regarding their flagella?

Gram-positive have one set of rings and a single membrane Signup and view all the answers

What distinguishes the slime layer from the capsule form of glycocalyx?

Capsule is well organized and tightly attached Signup and view all the answers

In what form is DNA stored in bacteria?

Circular chromosome in nucleoid Signup and view all the answers

What type of flagellar arrangement consists of flagella located all around the bacterium?

Peritrichous Signup and view all the answers

Which of the following accurately describes the cytoplasm of a cell?

All cell structures and the fluid combined Signup and view all the answers

What is the primary function of fimbrae in bacteria?

To attach to specific surfaces Signup and view all the answers

Which of the following statements best describes the differences between Gram positive and Gram negative bacteria?

Gram positive bacteria have a thick peptidoglycan layer and teichoic acids. Signup and view all the answers

What is the function of a pilus in bacteria?

To enable bacterial conjugation Signup and view all the answers

Which of the following best explains the term 'lipid A'?

It is an endotoxin that triggers a strong immune response. Signup and view all the answers

What substance primarily composes the bacterial cell wall?

Peptidoglycan Signup and view all the answers

Under what conditions are endospores formed by bacteria?

Under harsh environmental conditions Signup and view all the answers

What is the role of porins in Gram negative bacteria?

To serve in selective permeability for nutrients Signup and view all the answers

How do catabolic reactions differ from anabolic reactions?

Catabolic reactions release energy through the breakdown of large molecules. Signup and view all the answers

Which structure of bacteria is dynamic and described by the fluid mosaic model?

Cell membrane Signup and view all the answers

Which of the following is true regarding Mycoplasma bacteria?

They do not have a cell wall. Signup and view all the answers

What is the main function of enzymes in chemical reactions?

To speed up chemical reactions Signup and view all the answers

Which of the following best describes a coenzyme?

An organic cofactor derived from vitamins Signup and view all the answers

What distinguishes an active site from an allosteric site?

Active site is where substrate binding alters enzyme shape, while allosteric site is a separate binding location Signup and view all the answers

Which statement accurately describes feedback inhibition?

The end product of a metabolic pathway inhibits an enzyme Signup and view all the answers

During which phase of glycolysis is ATP consumed?

Energy investment phase Signup and view all the answers

Which pathway does not use oxygen as a final electron acceptor?

Anaerobic respiration Signup and view all the answers

What is produced during the energy payoff phase of glycolysis?

4 ATP, 2 NADH, and 2 pyruvate Signup and view all the answers

What is the primary outcome of competitive inhibition?

Substrates and inhibitors compete for the active site Signup and view all the answers

Which process breaks down glucose into 2-pyruvate molecules?

Glycolysis Signup and view all the answers

Which enzymatic pathways utilizes an electron transport chain?

Aerobic respiration Signup and view all the answers

Study Notes

Shared Structures of Eukaryotes and Prokaryotes

Common structures: plasma membrane, cytoplasm, ribosomes, and DNA.

Unique Structures in Prokaryotes

Contains circular DNA, cell membrane, cytoplasm, and bacterial flagella.

Unique Structures in Eukaryotes

Comprises linear DNA, plasma membrane, endomembrane system, mitochondria, chloroplasts, flagella, and cilia.

DNA Storage

Prokaryotic DNA: stored in a singular circular chromosome located in the nucleoid.
Eukaryotic DNA: stored in multiple linear chromosomes within the nucleus.

Cytoplasm vs. Cytosol

Cytoplasm includes all cell structures and fluid.
Cytosol refers specifically to the fluid component.

Flagella Differences

Prokaryotic flagella are simpler, rotating to propel the cell.
Eukaryotic flagella exhibit a complex, whip-like motion.

Bacterial Reproduction

Bacteria primarily reproduce by binary fission, resulting in two daughter cells.

Pleomorphic Bacteria

Pleomorphic bacteria can vary in size and shape.

Bacterial Arrangements

Diplo: pairs
Strepto: chains
Staphylo: clusters
Tetrads: groups of four

Glycocalyx

A gelatinous layer surrounding some bacterial cells, aiding in protection and attachment.

Forms of Glycocalyx

Capsule: well-organized, tightly attached.
Slime Layer: less organized, loosely attached.

Glycocalyx Functions

Traps nutrients, aids in surface attachment, and helps evade host immune responses.

Flagellum Function

Provides mobility, allowing bacteria to respond to environmental stimuli.

Flagella Arrangements

Monotrichous: single flagellum.
Amphitrichous: one or more flagella at each end.
Lophotrichous: cluster of flagella at one end.
Peritrichous: flagella distributed around the cell.

Flagellum Components

Filament: outer region extending from the cell.
Hook: connects the filament to the cell surface.
Basal body: anchors the flagellum to the cell wall and plasma membrane.

Gram Positive vs. Gram Negative Flagella

Gram Positive: has one set of rings, a single membrane, and a thick peptidoglycan layer.
Gram Negative: contains two sets of rings, two membranes (outer and inner), and a thin peptidoglycan layer.

Flagellum Movement

Movement generated by changing flagellar rotation; straight runs occur with stimuli, and more tumbling happens without stimuli.

Endoflagella

Found in spirochetes, providing unique movement capabilities.

Fimbriae Function

Hair-like structures used for attachment to specific surfaces.

Pilus Function

Facilitates bacterial conjugation, transferring genetic material between bacteria.

Cell Wall Function

Maintains bacterial shape and prevents lysis.

Bacterial Cell Wall Composition

Contains peptidoglycans made up of N-acetylglucosamine (NAG) and N-acetylmuramic acid (NAM), along with tetrapeptides.

Gram Positive vs. Gram Negative Cell Walls

Gram Positive: thick peptidoglycan layer with teichoic acids.
Gram Negative: thin peptidoglycan layer, outer membrane containing lipopolysaccharides (LPS).

Lipopolysaccharides (LPS)

Macromolecules found in Gram negative outer membranes, serving as virulent factors and triggering strong immune responses.

Mycoplasma Bacteria

Lack a cell wall, making them unique among bacteria.

Fluid Mosaic Model

Describes the cell membrane as a dynamic structure composed of a phospholipid bilayer with proteins that move fluidly.

Phospholipids

Contain hydrophilic phosphate heads and hydrophobic fatty acid tails, creating a bilayer.

Endospores

Highly resistant, dormant structures formed by bacteria under harsh environmental conditions.

Metabolism Overview

Metabolism encompasses all chemical reactions maintaining life, with energy stored as ATP.

Catabolic vs. Anabolic Reactions

Catabolic reactions break down large molecules, releasing energy.
Anabolic reactions synthesize larger molecules from smaller ones, consuming energy.

Enzymes

Catalysts that speed up reactions by binding substrates to active sites; can have cofactors (inorganic) and coenzymes (organic, derived from vitamins).

Active vs. Allosteric Sites

Active site: where substrate binds.
Allosteric site: alternative binding site that can affect enzyme activity.

Pathway Modulation Mechanisms

Competitive inhibition: substrate competes for the active site.
Non-competitive inhibition: alters enzyme shape, preventing substrate binding.
Feedback inhibition: end products inhibit an upstream enzyme.

Glycolysis Overview

Breaks down glucose into 2 pyruvate, divided into an energy investment phase (uses 2 ATP) and an energy payoff phase (produces 4 ATP, 2 NADH, and 2 pyruvate).

Glucose Catabolism Pathways

Aerobic respiration: uses oxygen as the final electron acceptor.
Anaerobic respiration: does not use oxygen but employs an alternative electron acceptor.
Anaerobic fermentation: occurs without oxygen or electron transport chain participation.

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Description

Explore the similarities and differences between eukaryotic and prokaryotic cells in this quiz. Understand the shared structures, unique characteristics, and how DNA is stored in both cell types. Test your knowledge on cellular biology fundamentals.