Unit One Review: Chapters 3 and 6
Chapter 3: Water and the Fitness of the Environment
- Section 3.1 The polarity of water molecules results in hydrogen bonding
- Water is made of 2 hydrogen atoms joined to one oxygen atom by single covalent bonds
- Water is a polar molecule meaning that opposite ends of the molecule have opposite charges
- Water is made of 2 hydrogen atoms joined to one oxygen atom by single covalent bonds
- Section 3.2 Four emergent properties of water contribute to Earth's fitness for life
- Cohesion
- The binding together of like molecules- often by hydrogen bonds
- Water molecules stick together by cohesion
- The binding together of like molecules- often by hydrogen bonds
- Adhesion
- The clinging of one substance to another
- This property allows the water to counter the pull of gravity during transpiration
- The clinging of one substance to another
- Surface Tension
- A measure of how difficult it is to stretch or break the surface of a liquid
- Water has a higher surface tension to most other molecules
- A measure of how difficult it is to stretch or break the surface of a liquid
- Moderation of Temperature
- Water has a very high specific heat
- The amount of heat required to raise or lower the temperature of a substance by 1 degree C.
- Water's high specific heat is essential to our survival and maintaining a relatively moderate climate
- The amount of heat required to raise or lower the temperature of a substance by 1 degree C.
- Evaporative cooling
- The property of a liquid whereby the surface becomes cooler during evaporation owing a loss of highly kinetic molecules to the gaseous state
- Contributes to the stability of the temperature in lakes and ponds
- Provides a mechanism that prevents terrestrial organisms from overheating
- Ice helps keep organisms in bodies of water from freezing, it works like an insulator
- The property of a liquid whereby the surface becomes cooler during evaporation owing a loss of highly kinetic molecules to the gaseous state
- The Solvent of Life
- An aqueous solution is one in which water is the solvent
- Water is the closest thing to a universal solvent
- An aqueous solution is one in which water is the solvent
- Hydrophilic substances
- Any substance that has an affinity for water
- Can be hydrophilic and not dissolve
- i.e. glucose
- Any substance that has an affinity for water
- Hydrophobic substances
- Any substance that does NOT have an affinity for water
- Are nonionic and nonpolar substances
- i.e. vegetable oil
- Any substance that does NOT have an affinity for water
- molarity
- the number of moles of solute per liter of solution
- the number of moles of solute per liter of solution
- Section 3.3 Dissociation of water molecules leads to acidic and basic conditions that affect living organisms
- ocassionally a hydrogen ion that is participating in a hydrogen bond between two water molecules shifts from one molecule to another
- an acid is a substance that is increases the hydrogen ion concentration of a solution
- a substance that reduces the hydrogen concentration is a base
- Buffers are substances that minimize changes in the concentrations of H+ and OH-
- an acid is a substance that is increases the hydrogen ion concentration of a solution
- Review Questions
- The bonds that are broken when water vaporizes are:
- Ionic bonds
- Bonds between water molecules
- Bonds between atoms within individual water molecules
- Polar covalent bonds
- Nonpolar covalent bonds
- Ionic bonds
- Which of the following is an example of a hydrophobic material?
- Paper
- Table salt
- Wax
- Sugar
- Pasta
- Paper
Chapter 6: A Tour of the Cell
- Section 6.1 to study the cells, biologists use microscopes and the tools of biochemistry
- Light microscopes
- Visible light is passed through the specimen and then passed through the specimen or onto the surface
- Visible light is passed through the specimen and then passed through the specimen or onto the surface
- Electron microscope
- Focuses a beam of electrons through the specimen or onto its surface
- Two basic types of electron microscopes
- Sacanning electron microscope
- Transmission electron microscope
- Sacanning electron microscope
- Focuses a beam of electrons through the specimen or onto its surface
- Section 6.2/ 6.3
- Comparing prokaryotic and eukaryotic cells
- Comparing prokaryotic and eukaryotic cells
Characteristics | Pro cells | Eu cells |
Plasma membrane | Yes | Yes |
Cytosol w/ organelles | Yes | Yes |
Ribosomes | Yes | Yes |
Nucleus | No | Yes |
Size | 1-10 micrometers | 10-100 micrometers |
Internal membranes | No | yes |
- Prokaryotic cell
- Prokaryotic cells include bacteria and archaebacteria
- Details include:
- No membrane bound nucleus
- No membrane bound organelles
- Smaller than eukaryotes
- No membrane bound nucleus
- Prokaryotic cells include bacteria and archaebacteria
- Eukaryotic cells
- Eukaryotic cells are animal and plant cells
- Details include:
- Membrane bound organelles
- Membrane bound nucleus, which contains cell's chromosomes
- Much larger than prokaryotes
- Eukaryotic cells make up the kingdom's protista, fungi, plantae, and animalla
- Membrane bound organelles
- Eukaryotic cells are animal and plant cells
- The Nucleus: Genetic Library of the Cell
- Contains most of the genes in the eukaryotic cell
- Enclosed by the nuclear envelope which has a double membrane
- The nuclear side of the envelope is lined by the nuclear lamina
- The nuclear side of the envelope is lined by the nuclear lamina
- Within the nucleus DNA is organized into discrete units called chromosomes
- Contains most of the genes in the eukaryotic cell
- Ribosomes: Protein Factories in the Cell
- A cytoplasmic organelle that is the site for protein synthesis
- Free ribosomes- ribosomes suspended in the cytosol
- Attatched ribosomes- attatched to the outside of the endoplasmic reticulum
- Free ribosomes- ribosomes suspended in the cytosol
- Section 6.4 the endomembrane system regulates protein traffic and performs metabolic functions in the cell
- The endomembrane system includes:
- Nuclear envelope
- Endoplasmic reticulum
- Golgi apparatus
- Lysosomes
- Vacuoles
- Plasma membrane (related)
- Nuclear envelope
- Endoplasmic reticulum (ER) extensive membraneous network of tubules and sacs (cisternae) which sequesters its internal lumen (cristernal space) from the cytosol
- Smooth ER- synthesis of lipids, phospholipids and steroids, carbohydrate metabolism, detoxify drugs and poisons, and stores calcium for muscle contraction
- Rough ER- continuous with outer membrane of the nuclear envelope, manufactures secretory proteins
- Smooth ER- synthesis of lipids, phospholipids and steroids, carbohydrate metabolism, detoxify drugs and poisons, and stores calcium for muscle contraction
- Golgi Apparatus
- An organelle that is made of flattened, stacked membranous sacs that modify, store, and route products of the cell
- It also has distinct polarity, the cis face receives and the trans face pinches off vesicles for transport to other sites
- An organelle that is made of flattened, stacked membranous sacs that modify, store, and route products of the cell
- Lysosomes
- An organelle that is a membrane-enclosed bag of hydrolytic enzymes that digest all major classes of macromolecules
- Optimal PH is about 5
- Enzymes include carbohydrases, proteases, and nucleases
- Lysosomes pinch off from the trans face of the golgi apparatus
- An organelle that is a membrane-enclosed bag of hydrolytic enzymes that digest all major classes of macromolecules
- Vacuole
- An organelle which is a membrane- enclosed sac that is larger than a vesicle
- Contractile vacuole- vacuole formed by phagocytosis which is the site for cellular digestion in some plants and macrophages
- Food vacuole- large vacuole formed by phagocytosis which is the site for intracellular digestion in some protists and macrophages
- Central vacuole- large vacuole found in most mature plant cells
- Contractile vacuole- vacuole formed by phagocytosis which is the site for cellular digestion in some plants and macrophages
- Section 6.5 mitochondria and chloroplasts change energy from one form to another
- Mitochondria
- The sites of cellular respiration, a process that uses energy extracted from organic molecules to produce ATP
- Contains two layers
- Outer membrane- highly permeable to solutes, but it blocks the passage of proteins and other macromolecules
- Inner membrane- contains embedded enzymes that are involved in CR. The membrane's many infoldings or cristae increase the surface area available for these reactions to occur
- Outer membrane- highly permeable to solutes, but it blocks the passage of proteins and other macromolecules
- Chloroplasts
- The site of photosynthesis
- Divided into 3 functional compartments by a system of membranes
- Thylakoid space- segregates the interior of the chloroplast into two compartments
- Intermembrane space- seperates the double membrane
- Thylakoid- flattened membraneous sacs inside the chloroplast
- Thylakoid space- segregates the interior of the chloroplast into two compartments
- The site of photosynthesis
- Plastids
- A group of plant and algal membrane bound organelles that include amyloplasts, chromoplasts, and chloroplasts
- Amyloplasts- colorless plastids that store starch; particularily in roots and tubers
- Chromolpasts- have pigments that give fruites and flowers their yellow and orange hues
- Chloroplasts- the sites of photosynthesis (see above)
- Contain chlorophyll
- Contain chlorophyll
- Amyloplasts- colorless plastids that store starch; particularily in roots and tubers
- The sites of cellular respiration, a process that uses energy extracted from organic molecules to produce ATP
- Section 6.6 the cytoskeleton is a network of fibers that organize cell structures and activities in the cell
- The cytoskeleton
- A network of fibers that form a dynamic framework for movement, support, and regulation of the cell
- Give mechanical support to the cell and helps maintain its shape
- Mechanically transmits signals from the cell's surface to its interior
- Enables a cell to change shape
- Give mechanical support to the cell and helps maintain its shape
- Constructed by 3 types of fibers
- Microtubules- straight hollow fibers that are about 25nm in diameter and 200nm in length, constructed from tubulin
- Microfilaments- 7nm, constructed from actin, provide cellular support, participate in muscle contraction, and help with elongation and contraction of pseudopodia during amoeboid movement
- Intermediate filaments- (8-12nm) between microtubules and microfilaments, are constructed from keratin subunits, fix organelle position, reinforce cell shape, bear tension
- Intermediate filaments- (8-12nm) between microtubules and microfilaments, are constructed from keratin subunits, fix organelle position, reinforce cell shape, bear tension
- Other types of fibers
- Centrioles- a pair of cylindrical structures that are located in the centrosome of an animal cell. Composed of 9 sets of triplet microtublues and arranged in a ring
- Cilla and flagella- locomotor organelles found in eukaryotic cells. Assist in movement. Cilla is more numerous than flagella
- Centrioles- a pair of cylindrical structures that are located in the centrosome of an animal cell. Composed of 9 sets of triplet microtublues and arranged in a ring
- Microtubules- straight hollow fibers that are about 25nm in diameter and 200nm in length, constructed from tubulin
- Section 6.7 extracellular components and connections between cells help coordinate cellular activities
- Cell walls of plants
- Protect the plant cels and give support, contains 3 parts
- Primary cell wall- the first wall secreted by a young plant cell
- Middle lamella- a thin layer of polysaccharides that hold adjacent cells together
- Secondary cell wall- is secreted by a mature plant cell. It is strong and has a double matriz that affords the cell protection and support
- Primary cell wall- the first wall secreted by a young plant cell
- The extracellular matrix (ECM) of animal cells
- The fluid outside of animal cells, contains fibers of collagen, proteoglycans, fibronectin, and its proteins also bind to integrin
- The fluid outside of animal cells, contains fibers of collagen, proteoglycans, fibronectin, and its proteins also bind to integrin
- Intercellular junctions
- Plant cells contain channels which perforate the cell walls called plsasmodesmata. Cytosol passes through the plasmodesmata and connects the chemical environments of adjacent cells
- Junctions in animals
- Tight junctions
- The membranes of neighboring cells are tightly pressed together by specific proteins. They prevent the leakage of extracellular fluid across a layer of epithelial cells
- The membranes of neighboring cells are tightly pressed together by specific proteins. They prevent the leakage of extracellular fluid across a layer of epithelial cells
- Desosomes
- Contain intermediate filaments made of sturdy karatin proteins, they fasten adjacent cells together
- Contain intermediate filaments made of sturdy karatin proteins, they fasten adjacent cells together
- Gap junctions
- Provide cytoplasmic channels from one cell to an adjacent cell. Allows ions, sugars, amino acids, and other small molecules to pass
- Provide cytoplasmic channels from one cell to an adjacent cell. Allows ions, sugars, amino acids, and other small molecules to pass
- Plant cells contain channels which perforate the cell walls called plsasmodesmata. Cytosol passes through the plasmodesmata and connects the chemical environments of adjacent cells
- Review Questions
- Which of the follow is present in a prokaryotic cell?
- Mitochondrion
- Ribosome
- Chloroplast
- ER
- Nuclear envelope
- Mitochondrion
- Which of the following is NOT considered part of the endomembrane system?
- Nuclear envelope
- Chloroplast
- Golgi apparatus
- Plasma membrane
- ER
- Nuclear envelope
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