CORE B Flashcards
What are the basic units of proteins?
Amino acids
Amino acids are the fundamental building blocks of proteins.
What are the two functional groups present in all amino acids?
Amino group and carboxyl group
These groups are essential for the structure and function of amino acids.
What is the reaction called when amino acids are joined together?
Condensation reaction
This reaction forms a peptide bond and releases water.
What is the reverse reaction of a condensation reaction?
Hydrolysis
Hydrolysis involves the use of water to split peptide bonds.
What is formed when many amino acids are joined by peptide bonds?
Polypeptide
A polypeptide is a chain of amino acids linked by peptide bonds.
What are the four levels of protein structure?
Primary, secondary, tertiary, quaternary
Each level describes a different aspect of protein organization.
What does the primary structure of a protein refer to?
The sequence of amino acids in a polypeptide chain
The primary structure determines the protein’s unique characteristics.
What is the secondary structure of a protein?
The way a polypeptide chain is folded
This includes structures like alpha-helices and beta-sheets.
What describes the tertiary structure of a protein?
The three-dimensional shape of a protein
This shape is formed by the folding of the polypeptide chain and interactions between its segments.
What is the quaternary structure of a protein?
The formation of a functional protein from two or more polypeptide chains
An example is hemoglobin, which consists of four polypeptide chains.
Fill in the blank: The parts of amino acids that are different in each type of amino acid are called _______.
R groups
R groups determine the unique properties of each amino acid.
True or False: Not all proteins have a quaternary structure.
True
Some proteins consist of a single polypeptide chain and do not form quaternary structures.
What are the basic units of carbohydrates?
Monosaccharides
Monosaccharides are composed of carbon, hydrogen, and oxygen.
What is formed when two monosaccharides combine?
Disaccharides
Disaccharides are formed by a condensation reaction between two monosaccharides.
What type of bond is formed between monosaccharides in disaccharides?
Glycosidic bond
What is the process called when monosaccharides combine to form disaccharides?
Condensation reaction
What is a polysaccharide?
A polymer of many monosaccharide units joined by glycosidic bonds.
What is the primary function of carbohydrates in the body?
Source of energy
How is glucose stored in the body?
In the form of glycogen
What are the three types of carbohydrates?
- Monosaccharides
- Disaccharides
- Polysaccharides
What are triglycerides formed from?
One molecule of glycerol and three molecules of fatty acids.
What distinguishes a phospholipid from a triglyceride?
One fatty acid is substituted by a phosphate-containing group.
Fill in the blank: Lipids are not _______ even though they are formed in condensation reactions.
polymers
What are the two main components of a triglyceride?
- Glycerol
- Fatty acids
What role do lipids play in the body?
- Energy source
- Thermal insulation
- Physical protection
What structure determines the function of enzymes?
Tertiary structure
What is the active site of an enzyme?
The part of the enzyme where substrates bind.
What is the relationship between the shape of the active site and the substrate?
The shape of the active site is complementary to the shape of the substrate.
True or False: Enzymes can act on multiple substrates regardless of their shape.
False
What are substrates in the context of enzymes?
Substances on which an enzyme acts to form the products.
What happens if there is a change in the shape of the enzyme’s active site?
Substrates will no longer bind effectively.
What is the effect of increasing temperature on enzyme activity?
Enzyme activity increases up to about 40°C, after which it rapidly decreases due to denaturation.
What happens to the enzyme’s active site when the temperature is too high?
The shape of the active site changes, preventing substrates from fitting correctly.
What is denaturation in the context of enzymes?
Denaturation is the process where the enzyme loses its structure and functionality due to high temperature or other factors.
Define diffusion.
Diffusion is the movement of a substance from an area of high concentration to an area of low concentration.
How are gills and lungs adapted for diffusion?
They have thin walls to minimize the distance for diffusion, maximizing the rate of gas exchange.
What are the roles of carbohydrases in digestion?
Carbohydrases convert disaccharides into monosaccharides, such as starch into maltose.
What do proteases do?
Proteases convert proteins into smaller polypeptides or amino acids.
What is the relationship between surface area and volume in multicellular organisms?
Multicellular organisms have a lower surface area to volume ratio, necessitating specialized exchange mechanisms.
What is the significance of the surface area to volume ratio?
A larger surface area relative to volume facilitates efficient exchange of substances.
True or False: Enzymes are only involved in metabolic reactions.
False. Enzymes are involved in both metabolic reactions and the digestion of foods.
Fill in the blank: The maximum distance for diffusion is ______.
15 cm
What is a key characteristic of the active site of an enzyme?
The active site has a complementary shape to the substrate.
How does temperature affect the rate of enzyme-catalyzed reactions?
The rate of reaction increases with temperature until the optimum temperature, after which it decreases.
What are lipases responsible for in digestion?
Lipases convert triglycerides into glycerol and fatty acids.
Why can’t large multicellular organisms rely solely on simple diffusion?
They have a low surface area to volume ratio, which limits the efficiency of diffusion.
What process occurs when soluble proteins in a raw egg are cooked?
They are denatured into insoluble proteins.
What is the effect of increasing temperature on enzyme activity?
Enzyme activity increases up to about 40°C, after which it rapidly decreases due to denaturation.
What happens to the enzyme’s active site when the temperature is too high?
The shape of the active site changes, preventing substrates from fitting correctly.
What is denaturation in the context of enzymes?
Denaturation is the process where the enzyme loses its structure and functionality due to high temperature or other factors.
Define diffusion.
Diffusion is the movement of a substance from an area of high concentration to an area of low concentration.
How are gills and lungs adapted for diffusion?
They have thin walls to minimize the distance for diffusion, maximizing the rate of gas exchange.
What are the roles of carbohydrases in digestion?
Carbohydrases convert disaccharides into monosaccharides, such as starch into maltose.
What do proteases do?
Proteases convert proteins into smaller polypeptides or amino acids.
What is the relationship between surface area and volume in multicellular organisms?
Multicellular organisms have a lower surface area to volume ratio, necessitating specialized exchange mechanisms.
What is the significance of the surface area to volume ratio?
A larger surface area relative to volume facilitates efficient exchange of substances.
True or False: Enzymes are only involved in metabolic reactions.
False. Enzymes are involved in both metabolic reactions and the digestion of foods.
Fill in the blank: The maximum distance for diffusion is ______.
15 cm
What is a key characteristic of the active site of an enzyme?
The active site has a complementary shape to the substrate.
How does temperature affect the rate of enzyme-catalyzed reactions?
The rate of reaction increases with temperature until the optimum temperature, after which it decreases.
What are lipases responsible for in digestion?
Lipases convert triglycerides into glycerol and fatty acids.
Why can’t large multicellular organisms rely solely on simple diffusion?
They have a low surface area to volume ratio, which limits the efficiency of diffusion.
What process occurs when soluble proteins in a raw egg are cooked?
They are denatured into insoluble proteins.
What is the structure that acts as a barrier to diffusion in cell membranes?
Phospholipid bilayer
The phospholipid bilayer is crucial for maintaining the integrity of the cell by controlling the movement of substances in and out.
What model describes the structure of the plasma membrane?
Fluid mosaic model
This model illustrates the dynamic nature of the membrane, where components can move laterally within the layer.
What type of molecules can pass through the phospholipid bilayer easily?
Non-polar molecules
Non-polar molecules such as oxygen and carbon dioxide can diffuse through the membrane because they are hydrophobic.
What is the term for substances that repel water?
Hydrophobic
Hydrophobic substances do not mix with water and are typically non-polar.
What does it mean for a membrane to be partially permeable?
Allows certain substances to pass while blocking others
This property is essential for maintaining cellular homeostasis.
What is the term for substances that attract water?
Hydrophilic
Hydrophilic substances can interact with water and are typically polar.
Fill in the blank: The movement of molecules from an area of high concentration to an area of low concentration is known as _______.
Diffusion
Diffusion is a passive transport mechanism that does not require energy.
What are the three main processes of passive transport?
- Simple diffusion
- Facilitated diffusion
- Osmosis
These processes allow substances to move across the membrane without the expenditure of energy.
True or False: Water is a polar molecule.
True
Water’s polarity allows it to dissolve many substances, making it an essential solvent in biological systems.
What type of proteins span the membrane and are exposed on both sides?
Transmembrane proteins
These proteins play critical roles in transport and signaling across the cell membrane.
What is the role of cholesterol in the plasma membrane?
Stabilizes the membrane fluidity
Cholesterol helps maintain the integrity and flexibility of the membrane.
Fill in the blank: The epithelial cells that line the small intestine have projections called _______ to increase surface area.
Microvilli
Microvilli enhance absorption efficiency in the intestine.
What is the effect of a larger surface area to volume ratio on metabolic rate?
Increases the metabolic rate
Animals with a larger surface area to volume ratio, like mice, tend to have higher metabolic demands.
What are specialized transport mechanisms needed for?
Transport of polar substances
Polar substances, such as glucose and amino acids, require specific transport proteins to cross the membrane.
What is the main solvent in biological systems?
Water
Water’s properties make it essential for biochemical reactions and processes.
What is facilitated diffusion?
Passive transport of substances through a membrane via specific proteins
This process assists polar and charged molecules in crossing the membrane without energy expenditure.
What is the structure that acts as a barrier to diffusion in cell membranes?
Phospholipid bilayer
The phospholipid bilayer is crucial for maintaining the integrity of the cell by controlling the movement of substances in and out.
What model describes the structure of the plasma membrane?
Fluid mosaic model
This model illustrates the dynamic nature of the membrane, where components can move laterally within the layer.
What type of molecules can pass through the phospholipid bilayer easily?
Non-polar molecules
Non-polar molecules such as oxygen and carbon dioxide can diffuse through the membrane because they are hydrophobic.
What is the term for substances that repel water?
Hydrophobic
Hydrophobic substances do not mix with water and are typically non-polar.
What does it mean for a membrane to be partially permeable?
Allows certain substances to pass while blocking others
This property is essential for maintaining cellular homeostasis.
What is the term for substances that attract water?
Hydrophilic
Hydrophilic substances can interact with water and are typically polar.
Fill in the blank: The movement of molecules from an area of high concentration to an area of low concentration is known as _______.
Diffusion
Diffusion is a passive transport mechanism that does not require energy.
What are the three main processes of passive transport?
- Simple diffusion
- Facilitated diffusion
- Osmosis
These processes allow substances to move across the membrane without the expenditure of energy.
True or False: Water is a polar molecule.
True
Water’s polarity allows it to dissolve many substances, making it an essential solvent in biological systems.
What type of proteins span the membrane and are exposed on both sides?
Transmembrane proteins
These proteins play critical roles in transport and signaling across the cell membrane.
What is the role of cholesterol in the plasma membrane?
Stabilizes the membrane fluidity
Cholesterol helps maintain the integrity and flexibility of the membrane.
Fill in the blank: The epithelial cells that line the small intestine have projections called _______ to increase surface area.
Microvilli
Microvilli enhance absorption efficiency in the intestine.
What is the effect of a larger surface area to volume ratio on metabolic rate?
Increases the metabolic rate
Animals with a larger surface area to volume ratio, like mice, tend to have higher metabolic demands.
What are specialized transport mechanisms needed for?
Transport of polar substances
Polar substances, such as glucose and amino acids, require specific transport proteins to cross the membrane.
What is the main solvent in biological systems?
Water
Water’s properties make it essential for biochemical reactions and processes.
What is facilitated diffusion?
Passive transport of substances through a membrane via specific proteins
This process assists polar and charged molecules in crossing the membrane without energy expenditure.
