How does competitive inhibition alter an enzyme's Michaelis constant (Km) and maximum reaction velocity (Vmax)?

Competitive inhibitors increase apparent Km (requiring higher substrate concentration) while leaving Vmax unchanged.

What four chemical groups are bonded to the central alpha-carbon in all standard amino acids?

1. An amino group (-NH2) 2. A carboxyl group (-COOH) 3. A hydrogen atom (-H) 4. A variable side chain (R-group).

How do starch and cellulose differ in their glycosidic bonds and resulting biological digestibility in humans?

Starch contains alpha-1,4 and alpha-1,6 glycosidic bonds digestible by human amylases; cellulose contains beta-1,4 glycosidic bonds which human enzymes cannot hydrolyze.

Why is a phospholipid described as an amphipathic molecule?

It contains both a hydrophilic polar phosphate head group and two hydrophobic nonpolar fatty acid tails.

Which covalent linkage connects two monosaccharides to form a disaccharide, and what reaction forms it?

A glycosidic bond formed via a condensation (dehydration synthesis) reaction.

Which specific functional groups participate in forming a peptide bond between two amino acids?

The alpha-carboxyl group of one amino acid reacts with the alpha-amino group of another, releasing water.

Why is the inner mitochondrial membrane extensively folded into cristae?

To increase the surface area available for electron transport chain complexes and ATP synthase enzymes.

What is the difference between simple diffusion and facilitated diffusion across a cell membrane?

Simple diffusion allows small, nonpolar molecules to pass directly through the lipid bilayer; facilitated diffusion requires transmembrane channel or carrier proteins without energy expenditure.

How does primary active transport differ fundamentally from secondary active transport?

Primary active transport directly hydrolyzes ATP to move solutes against their gradient (e.g., Na+/K+ ATPase); secondary active transport uses the electrochemical gradient created by primary transport.

Why does the hydrolysis of the terminal phosphoanhydride bond of ATP yield large amounts of free energy?

It relieves electrostatic repulsion between adjacent negative charges on phosphate groups and produces resonance-stabilized inorganic phosphate (Pi).

What motor proteins travel along microtubules, and what are their respective directional movements?

Kinesins generally move toward the plus end (anterograde/periphery), while dyneins move toward the minus end (retrograde/centrosome).

What vital metabolic role do peroxisomes play in eukaryotic cells?

Breaking down long-chain fatty acids via beta-oxidation and detoxifying hydrogen peroxide (H2O2) into water and oxygen using catalase.

How does non-competitive (allosteric) inhibition alter an enzyme's Michaelis constant (Km) and maximum velocity (Vmax)?

Non-competitive inhibitors decrease Vmax by inactivating catalytic activity while leaving Km unchanged.

According to the fluid mosaic model, what determines the fluidity of the plasma membrane?

Phospholipid fatty acid saturation (unsaturated kinks increase fluidity), temperature, and cholesterol content.

What is the characteristic empirical formula and monomeric building block of carbohydrates?

General empirical formula (CH2O)n, with monosaccharides (such as glucose, fructose, and galactose) serving as monomer units.

How does cholesterol regulate plasma membrane fluidity at high versus low temperatures?

At high temperatures, cholesterol hinders phospholipid movement to reduce fluidity; at low temperatures, it prevents tight packing to inhibit crystallization and freezing.

Which three filamentous protein polymers make up the eukaryotic cytoskeleton?

Microfilaments (actin), intermediate filaments (e.g., keratins, lamins), and microtubules (alpha/beta tubulin dimers).

What are the three core tenets of classical cell theory?

1. All living organisms are composed of one or more cells. 2. The cell is the basic structural and functional unit of life. 3. All cells arise from pre-existing cells through division.

What happens to a red blood cell placed into a hypertonic solution versus a hypotonic solution?

In a hypertonic solution, water leaves the cell causing crenation (shriveling); in a hypotonic solution, water rushes in causing hemolysis (cell swelling and bursting).

What structural feature distinguishing prokaryotes from eukaryotes is absent in bacterial cells?

A membrane-bound nucleus and membrane-bound organelles (prokaryotes possess a nucleoid instead).

Which non-covalent and covalent interactions determine the tertiary structure of a globular protein?

Hydrophobic interactions, hydrogen bonds, ionic bonds (salt bridges), van der Waals forces, and covalent disulfide bridges between cysteine residues.

What types of interactions stabilize secondary protein structures such as alpha-helices and beta-pleated sheets?

Hydrogen bonds between the carbonyl oxygen (C=O) and amide hydrogen (N-H) of the polypeptide polypeptide backbone.

What is the stoichiometric ion exchange ratio of the sodium-potassium pump (Na+/K+ ATPase) per hydrolyzed ATP?

Pumps 3 Na+ ions out of the cell and 2 K+ ions into the cell, making it an electrogenic pump.

How do biological catalysts (enzymes) accelerate biochemical reaction rates?

Enzymes lower the Gibbs free energy of activation (activation energy, Ea) without changing the overall standard free energy change (delta G) or reaction equilibrium.

Why do saturated fatty acids have higher melting temperatures than unsaturated fatty acids of equivalent chain length?

Saturated fatty acids have straight hydrocarbon chains lacking double bonds, allowing tight van der Waals packing, unlike kinked cis-unsaturated bonds.

What is the primary function of the Golgi apparatus?

Modifying, sorting, packaging, and tagging proteins and lipids from the ER into vesicles for secretion or delivery to other organelles.

What are the structural components of a triglyceride molecule?

One glycerol molecule esterified to three fatty acid chains.

What are the three chemical constituents of a single nucleotide monomer?

A five-carbon pentose sugar (ribose or deoxyribose), a nitrogenous base (purine or pyrimidine), and one or more phosphate groups.

How do rough endoplasmic reticulum and smooth endoplasmic reticulum differ in structure and primary function?

Rough ER is studded with ribosomes and specializes in protein synthesis and folding; smooth ER lacks ribosomes and synthesizes lipids, phospholipids, and detoxifies chemicals.

What structural differences distinguish RNA from DNA at the sugar and base levels?

RNA contains a ribose sugar (with a 2'-OH group) and the pyrimidine base uracil (U), whereas DNA contains 2'-deoxyribose (lacking 2'-OH) and thymine (T).

Mikrobiologie — Grundstufe (A1/A2) 3: Cell Biology & Biomolecules

[Deutsch] Mikrobiologie: Fundamental cell structures, organelles, membrane transport, and key biomolecules (carbohydrates, lipids, proteins, nucleic acids)

Level: basic
Languages: de → de
Cards: 32
Markdown: Mikrobiologie — Grundstufe (A1/A2) 3: Cell Biology & Biomolecules (.md)

Flashcards (32)

#	Front (Term / Question)	Back (Definition / Answer)
1	How does competitive inhibition alter an enzyme's Michaelis constant (Km) and maximum reaction velocity (Vmax)?	Competitive inhibitors increase apparent Km (requiring higher substrate concentration) while leaving Vmax unchanged.
2	What four chemical groups are bonded to the central alpha-carbon in all standard amino acids?	1. An amino group (-NH2) 2. A carboxyl group (-COOH) 3. A hydrogen atom (-H) 4. A variable side chain (R-group).
3	How do starch and cellulose differ in their glycosidic bonds and resulting biological digestibility in humans?	Starch contains alpha-1,4 and alpha-1,6 glycosidic bonds digestible by human amylases; cellulose contains beta-1,4 glycosidic bonds which human enzymes cannot hydrolyze.
4	Why is a phospholipid described as an amphipathic molecule?	It contains both a hydrophilic polar phosphate head group and two hydrophobic nonpolar fatty acid tails.
5	Which covalent linkage connects two monosaccharides to form a disaccharide, and what reaction forms it?	A glycosidic bond formed via a condensation (dehydration synthesis) reaction.
6	Which specific functional groups participate in forming a peptide bond between two amino acids?	The alpha-carboxyl group of one amino acid reacts with the alpha-amino group of another, releasing water.
7	Why is the inner mitochondrial membrane extensively folded into cristae?	To increase the surface area available for electron transport chain complexes and ATP synthase enzymes.
8	What is the difference between simple diffusion and facilitated diffusion across a cell membrane?	Simple diffusion allows small, nonpolar molecules to pass directly through the lipid bilayer; facilitated diffusion requires transmembrane channel or carrier proteins without energy expenditure.
9	How does primary active transport differ fundamentally from secondary active transport?	Primary active transport directly hydrolyzes ATP to move solutes against their gradient (e.g., Na+/K+ ATPase); secondary active transport uses the electrochemical gradient created by primary transport.
10	Why does the hydrolysis of the terminal phosphoanhydride bond of ATP yield large amounts of free energy?	It relieves electrostatic repulsion between adjacent negative charges on phosphate groups and produces resonance-stabilized inorganic phosphate (Pi).
11	What motor proteins travel along microtubules, and what are their respective directional movements?	Kinesins generally move toward the plus end (anterograde/periphery), while dyneins move toward the minus end (retrograde/centrosome).
12	Which organelle contains hydrolytic acid hydrolases with an optimal pH around 4.5–5.0 for macromolecule degradation?	The lysosome.
13	What vital metabolic role do peroxisomes play in eukaryotic cells?	Breaking down long-chain fatty acids via beta-oxidation and detoxifying hydrogen peroxide (H2O2) into water and oxygen using catalase.
14	How does non-competitive (allosteric) inhibition alter an enzyme's Michaelis constant (Km) and maximum velocity (Vmax)?	Non-competitive inhibitors decrease Vmax by inactivating catalytic activity while leaving Km unchanged.
15	According to the fluid mosaic model, what determines the fluidity of the plasma membrane?	Phospholipid fatty acid saturation (unsaturated kinks increase fluidity), temperature, and cholesterol content.
16	What is the characteristic empirical formula and monomeric building block of carbohydrates?	General empirical formula (CH2O)n, with monosaccharides (such as glucose, fructose, and galactose) serving as monomer units.
17	How does cholesterol regulate plasma membrane fluidity at high versus low temperatures?	At high temperatures, cholesterol hinders phospholipid movement to reduce fluidity; at low temperatures, it prevents tight packing to inhibit crystallization and freezing.
18	Which nuclear subcompartment is the site of ribosomal RNA (rRNA) transcription and ribosome subunit assembly?	The nucleolus.
19	Which three filamentous protein polymers make up the eukaryotic cytoskeleton?	Microfilaments (actin), intermediate filaments (e.g., keratins, lamins), and microtubules (alpha/beta tubulin dimers).
20	What are the three core tenets of classical cell theory?	1. All living organisms are composed of one or more cells. 2. The cell is the basic structural and functional unit of life. 3. All cells arise from pre-existing cells through division.
21	What happens to a red blood cell placed into a hypertonic solution versus a hypotonic solution?	In a hypertonic solution, water leaves the cell causing crenation (shriveling); in a hypotonic solution, water rushes in causing hemolysis (cell swelling and bursting).
22	What structural feature distinguishing prokaryotes from eukaryotes is absent in bacterial cells?	A membrane-bound nucleus and membrane-bound organelles (prokaryotes possess a nucleoid instead).
23	Which non-covalent and covalent interactions determine the tertiary structure of a globular protein?	Hydrophobic interactions, hydrogen bonds, ionic bonds (salt bridges), van der Waals forces, and covalent disulfide bridges between cysteine residues.
24	What types of interactions stabilize secondary protein structures such as alpha-helices and beta-pleated sheets?	Hydrogen bonds between the carbonyl oxygen (C=O) and amide hydrogen (N-H) of the polypeptide polypeptide backbone.
25	What is the stoichiometric ion exchange ratio of the sodium-potassium pump (Na+/K+ ATPase) per hydrolyzed ATP?	Pumps 3 Na+ ions out of the cell and 2 K+ ions into the cell, making it an electrogenic pump.
26	How do biological catalysts (enzymes) accelerate biochemical reaction rates?	Enzymes lower the Gibbs free energy of activation (activation energy, Ea) without changing the overall standard free energy change (delta G) or reaction equilibrium.
27	Why do saturated fatty acids have higher melting temperatures than unsaturated fatty acids of equivalent chain length?	Saturated fatty acids have straight hydrocarbon chains lacking double bonds, allowing tight van der Waals packing, unlike kinked cis-unsaturated bonds.
28	What is the primary function of the Golgi apparatus?	Modifying, sorting, packaging, and tagging proteins and lipids from the ER into vesicles for secretion or delivery to other organelles.
29	What are the structural components of a triglyceride molecule?	One glycerol molecule esterified to three fatty acid chains.
30	What are the three chemical constituents of a single nucleotide monomer?	A five-carbon pentose sugar (ribose or deoxyribose), a nitrogenous base (purine or pyrimidine), and one or more phosphate groups.
31	How do rough endoplasmic reticulum and smooth endoplasmic reticulum differ in structure and primary function?	Rough ER is studded with ribosomes and specializes in protein synthesis and folding; smooth ER lacks ribosomes and synthesizes lipids, phospholipids, and detoxifies chemicals.
32	What structural differences distinguish RNA from DNA at the sugar and base levels?	RNA contains a ribose sugar (with a 2'-OH group) and the pyrimidine base uracil (U), whereas DNA contains 2'-deoxyribose (lacking 2'-OH) and thymine (T).