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Questions and Answers
What are the components that amino acids are made up of?
Which level of protein organization is characterized by the sequence of amino acids?
In a hypertonic solution, what occurs to a cell?
What type of bonding is primarily responsible for maintaining the tertiary structure of proteins?
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What happens in isotonic solutions regarding water movement across the cell membrane?
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What characteristic is essential for categorizing an organism as a plant?
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What is a primary role of plants in relation to atmospheric gases?
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Which component is NOT a characteristic of plant cells?
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What process contributes to the greenhouse effect as mentioned in the content?
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How do plants contribute to energy storage?
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What is the primary mechanism by which bamboo can grow over 1 meter a day?
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What type of bond involves the sharing of electrons between atoms?
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Which type of meristem is responsible for the increase in the length of a plant?
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What occurs during the formation of an ionic bond?
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What is the role of expansin proteins in plant cell walls?
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Carbon's ability to form multiple compounds is primarily due to its:
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What type of bond is characterized by partial positive and negative charges due to unequal sharing of electrons?
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What is the main component of plant bodies that enables them to grow?
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What type of bond is considered the weakest among hydrogen, ionic, and covalent bonds?
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Which characteristic describes hydrophilic molecules?
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What is the primary function of starch in plants?
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What type of bond connects the glucose molecules in cellulose?
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What is the process called by which disaccharides are formed from monosaccharides?
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Which of the following statements about hydrophobic molecules is true?
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Which bond strength ranking is accurate from weakest to strongest?
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What structural role does cellulose primarily serve in plants?
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Which type of chemical reaction occurs during the formation of polysaccharides?
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Which of the following correctly describes the structure of starch?
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What type of meristem is primarily responsible for increasing the length of a plant?
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Which of the following represents an organ formed by the shoot apical meristem?
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Which structure is responsible for increasing the girth of stems and roots in woody plants?
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What process allows plant cells to expand significantly during growth?
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Cauliflower is primarily composed of which type of plant structure?
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Which statement about secondary meristems is true?
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What is the role of expansin proteins in plant cells?
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Which of the following is NOT a characteristic of primary meristems?
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Study Notes
Plant Growth and Structure
- Plant bodies contain cells, tissues, organs, and organ systems.
- Plants grow by cell production and cell expansion.
- Primary apical meristems are located at the tips of shoots and axillary buds
- Primary apical meristems are responsible for increasing plant length
- Primary apical meristems generate tissues that make up organs
- Plant cell expansion is an increase in cytoplasm and number of organelles.
- Plant cells can take up a lot of water into the central vacuole and expand cell walls.
- Expansin proteins unlock linkages between cell wall components allowing the wall to stretch.
What Makes a Plant a Plant?
- Contain chlorophyll for absorbing light for photosynthesis
- Adapted for life on land
- Composed of many cells
- Cell walls contain cellulose
Energy Flow Overview
- Energy stored in bonds may be used quickly or much later.
Plants and Energy
- Plants convert carbon dioxide (CO2) into organic compounds.
- Plants are hosts for bacteria that consume atmospheric methane.
- Greenhouse gases: carbon dioxide, methane, and water vapor.
Greenhouse Effect
- Infared radiation (heat) from the sun passes through the atmosphere.
- The atmosphere traps infrared radiation inside, causing the interior to warm.
Organ Systems
- Fruit develops from the ovary after fertilization.
- Fruit contains seeds.
Covalent Bonds
- Form between atoms that share electrons.
- Some atoms may share more than one pair of electrons.
- Carbon has 4 electrons to share.
- Carbon can share two electrons with an oxygen or another carbon atom.
- Carbon or share one electron with two different atoms.
- Carbon can form many different compounds.
### Ionic Bonds
- One atom gives up one or more electrons and becomes positively-charged.
- Another atom takes electrons and becomes negatively-charged.
- The attraction between these oppositely-charged ions is called the ionic bond.
Hydrogen Bonds
- Form when electrons shared between two atoms that differ significantly in size.
- Electrons spend more time traveling around the larger atom.
- One portion of the molecule has a partial negative charge, called a polar molecule.
- The partial negative charge on one molecule is attracted to the partial positive charge on another molecule.
- This is called a hydrogen bond.
Amino Acids
- Composed of carbon, hydrogen, oxygen, nitrogen, and sometimes sulfur.
- The central carbon group is bonded to a carboxylic acid group (COOH), an amino group (NH2), and a side chain (R).
### Four Levels of Protein Organization
- Primary: Sequence of amino acids
- Secondary: Helical or pleated sheet structures maintained by hydrogen bonds
- Tertiary: Folding of protein with shape maintained by covalent bonds between sulfur atoms
- Quaternary: Two or more polypeptide chains held together by hydrogen bonds
Cell-Membrane Carrier Protein
- A type of membrane protein that facilitates the movement of molecules across the cell membrane.
### Membrane Functions
- Transport of water by osmosis: Diffusion of water across cell membranes.
- Water moves into or out of the cell depending on:
- Concentration of dissolved substances (solutes) on both sides of the membrane
- Pressure or physical force exerted on water.
- Water transport by osmosis does not need a carrier protein.
Osmosis
-
Isotonic Solution: Same solute concentration as inside the cell
- Some water will pass through the membrane in each direction.
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Hypotonic Solution: Lower concentration of solutes (higher concentration of water) than the inside of the cell.
- Water diffuses into the cell.
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Hypertonic Solution: Higher concentration of solutes (lower concentration of water) than the cell.
- Water diffuses out of the cell.
Hydrophilic and Hydrophobic
-
Hydrophilic: Water-loving
- Dissolve in water
- Charged or Polar
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Hydrophobic: Water-hating
- Do not dissolve in water
- Often dissolve in lipids
- Uncharged or nonpolar
Bond Strength
- Hydrogen Bond --> Ionic Bond --> Covalent Bond
- Hydrogen Bond: Partial charge (polar), water
- Ionic Bond: Full charge, salt, acids, bases
- Covalent Bond: Shared electrons, Carbon
Monosaccharides
- The flexible nature of carbohydrates makes them essential for a variety of biological processes.
- Single bonds at C1 allow the molecule to rotate.
- C1 reacts with OH of C5, resulting in ring formation and energy release.
Disaccharides
- Formed through dehydration synthesis.
- Two monosaccharides combine to form a disaccharide.
- Sucrose (table sugar) is a major sugar transported in plants
Polysaccharides
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Made by dehydration reactions.
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Not water-soluble (not hydrophilic).
-
Good for storage
-
Good for building structures
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Starch: Abundant polysaccharide in grains and root vegetables.
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Cellulose: Structural polysaccharide in plant cell walls.
- It is a polymer of glucose but arranged differently from starch.
- Alternate sugars are flipped.
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Humans cannot digest cellulose.
-
Some fungi and bacteria can.
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Cellulose is important for fiber in our diet.
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Description
Test your knowledge on plant growth, structure, and energy flow. This quiz covers everything from cell types to the role of chlorophyll in photosynthesis. Understand the basics of how plants develop and utilize energy for survival.
