Biology 2107 > Exam 1 Study > Flashcards

Exam 1 Study Flashcards

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1
Q

What is a hypothesis?

A

A tentative explanation that can be tested by experiments

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2
Q

The nucleus of a nitrogen atom contains 8 neutrons and 7 protons. What is it’s mass number and atomic number?

A

It has a mass number of 15 and an atomic number of 7

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3
Q

The chemical behavior of an atom depends primarily on what?

A

The number of electrons in the valence shell

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4
Q

What is an appropriate description of a covalent chemical bond?

A

Outer shell electrons of two atoms are shared so as to occupy the outer electron shells of both atoms

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5
Q

When two atoms are equally electronegative they will interact to form what bond?

A

They will form a nonpolar covalent bond

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6
Q

What functional group is most critical to energy metabolism in the cell?

A

The phosphate group

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7
Q

Where in the structure of a protein would glutamic acid be most likely?

A

On the exterior surface of the protein

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8
Q

If you located a single-stranded piece of nucleic acid in a cell, what would it be made of?

A

It would be made of nucleotides

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9
Q

Which nucleobases form pairs in DNA?

A

Thymine (T) and Adenine (A) pair. Cytosine (C) and Guanine (G) pair.

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10
Q

Which nucleobase does RNA use that DNA does not?

A

RNA uses Uracil (U) instead of Thymine (T)

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11
Q

Which sugar is most important for making RNA?

A

Ribose provides the sugar backbone that holds the molecule together and influences it’s structure and function

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12
Q

What is a large advantage of light microscopy over transmission electron microscopy?

A

Light microscopy allows you to view dynamic processes in living cells

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13
Q

What cellular structure is common to all three domains of life?

A

Ribosomes, as well as cell membrane and cytoplasm

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14
Q

Would a cell that specializes in synthesizing steroid hormones have a larger smooth or rough ER?

A

The smooth ER synthesizes lipids including steroid hormones, therefore, the cell would have a larger smooth ER

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15
Q

What is the correct order for the secretion of proteins from the cell?

A

Rough ER, golgi apparatus, transport vesicle, exocytosis

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16
Q

Autophagy removes old, damaged organelles like mitochondria. Which organelle is most critical for autophagy?

A

Lysosomes are the most critical

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17
Q

Why are mitochondria so prevalent in skeletal muscle?

A

Mitochondria produce energy for muscle contraction

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18
Q

What are functions of the cytoskeleton?

A

Structural support and cell shape, cellular locomotion, intracellular transport, cell division

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19
Q

What is an integral membrane protein?

A

A protein with it’s amino-terminus in the cytoplasm and it’s carboxyl-terminus in the extracellular space

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20
Q

What molecules will diffuse most quickly across a lipid bilayer?

A

Small nonpolar molecules

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21
Q

If a sugar needed by a cell was found at higher concentration inside the cell than outside, what would the cell need to do?

A

Perform active transport

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22
Q

You observe a cell that has a receptor protein that binds a signaling molecule that is produced by the same cell. What kind of signaling is occurring in this cell?

A

This is autocrine signaling?

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23
Q

You strip off all proteins on the cell surface by using a protease. Now, when you add a specific signaling molecule, the cell still responds. What is the most reasonable explanation of this?

A

The receptor for this signal is inside the cell, and the signaling molecule is nonpolar and can diffuse into the cell

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24
Q

What is passive transport?

A

No energy investment, down concentration gradient: High to low concentration

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25
What is active transport?
Requires energy investment, against concentration gradient: Low to high concentration
26
What is membrane potential?
The voltage across a membrane
27
What creates voltage in a membrane?
Differences in the distribution of anions and cations across a membrane
28
What drives the diffusion of ions across a membrane?
The electrochemical gradient
29
What are the two components of the electrochemical gradient?
* A chemical force (the ion’s concentration gradient) * An electrical force (charge differential between the inside and outside of the cell)
30
What do electrogenic pumps do?
Generate voltage across the membrane and store energy as an electrochemical gradient across the membrane
31
What is primary active transport coupled to?
ATP hydrolysis
32
What is cotransport?
Indirect active transport, such as H+ down concentration gradient coupled to sucrose against concentration gradient
33
If a sugar needed by a cell is found at a higher concentration inside the cell than outside, what must the cell do?
C. perform active transport
34
What occurs during exocytosis?
Transport vesicles migrate to the membrane, fuse with it, and release their contents
35
What is endocytosis?
The cell takes in molecules and particulate matter by forming new vesicles from the plasma membrane
36
What are the three types of endocytosis?
* Phagocytosis (“cellular eating”) * Pinocytosis (“cellular drinking”) * Receptor-mediated endocytosis
37
What are the essential elements for cell signaling?
* Signaling Cell * Signaling Molecule * Signal receptor (Protein) * Receptor cell
38
What type of signaling is occurring when a cell produces a signaling molecule that binds to its own receptor?
A. autocrine signaling
39
What are the stages when a target cell is exposed to a secreted signaling molecule?
* Signal reception * Signal Transduction * Cellular Response
40
What is a ligand?
Signaling molecule
41
What happens when a ligand binds to its receptor?
It causes a shape change in the receptor
42
What type of receptor is ionotropic?
Ligand-gated ion channel that is closed unless bound to its ligand
43
What are second messengers?
Small, nonprotein, water-soluble molecules or ions that spread throughout a cell by diffusion
44
What is a widely used second messenger?
Cyclic AMP (cAMP)
45
What does adenylyl cyclase do?
Converts ATP to cAMP in response to extracellular signals
46
What is the role of protein kinases?
Transfer phosphates from ATP to protein, a process called phosphorylation
47
What do protein phosphatases do?
Remove phosphates from proteins as inorganic phosphate
48
What is a phosphorylation cascade?
When many of the relay molecules in a signal transduction pathway are kinases, acting on other kinases
49
What is the cellular response related to transcription regulation?
Many signaling pathways regulate the synthesis of enzymes or other proteins, usually by turning genes on or off in the nucleus
50
What happens when a steroid hormone binds to its intracellular receptor?
The active form of the receptor enters the nucleus, acts as a transcription factor, and activates genes
51
If a specific signaling molecule causes a cell to respond even after stripping off all proteins on the cell surface, what is the most reasonable explanation?
D. The receptor for this signal is inside the cell, and the signaling molecule is nonpolar and can diffuse into the cell.
52
What does the plasma membrane exhibit that allows some substances to cross it more easily than others?
Selective permeability ## Footnote Selective permeability is a key feature of cell membranes that facilitates the regulation of substances entering and exiting the cell.
53
What is the major type of lipid found in cell membranes?
Phospholipids ## Footnote Phospholipids have hydrophilic heads and hydrophobic tails, forming the bilayer structure of membranes.
54
What model describes the structure of the plasma membrane?
Fluid Mosaic Model ## Footnote The Fluid Mosaic Model describes the membrane as a mosaic of different components that are fluid in nature.
55
What factors affect membrane fluidity?
* Temperature * Phospholipid composition * Length of fatty acid * Double bonds * Cholesterol ## Footnote Cholesterol acts as a fluidity buffer, maintaining membrane integrity across varying temperatures.
56
What type of proteins penetrate the hydrophobic interior of the bilayer?
Integral proteins ## Footnote Integral proteins are embedded within the lipid bilayer and play various roles, including transport and signaling.
57
What are peripheral proteins?
Proteins not embedded in the bilayer but loosely bound to the surface ## Footnote Peripheral proteins typically have functions associated with signaling and maintaining the cell's shape.
58
What is the function of membrane proteins?
* Transport * Enzymatic activity * Signal transduction * Cell-cell recognition * Intercellular joining * Attachment to cytoskeleton ## Footnote Membrane proteins facilitate various cellular functions, including communication and substance transport.
59
What does selective permeability of the plasma membrane allow?
Hydrophobic substances to pass more easily ## Footnote The hydrophobic interior of the membrane favors the passage of nonpolar molecules.
60
What type of transport involves movement of molecules without energy investment?
Passive transport ## Footnote Passive transport includes processes like diffusion, facilitated diffusion, and osmosis.
61
What is osmosis?
The diffusion of free water across a selectively permeable membrane ## Footnote Osmosis is a critical process in maintaining cell turgor and homeostasis.
62
What is tonicity?
Ability of surrounding solution to cause a cell to gain or lose water ## Footnote Tonicity influences cell shape and function, especially in animal cells.
63
What is the primary function of the Sodium-Potassium Pump?
To move sodium out and potassium into the cell against their concentration gradients ## Footnote This active transport mechanism is vital for maintaining cell potential and volume.
64
True or False: Active transport requires energy investment.
True ## Footnote Active transport mechanisms move substances against their concentration gradients, necessitating ATP.
65
Fill in the blank: The diffusion of molecules from high concentration to low concentration is called _______.
Diffusion ## Footnote This passive transport process continues until equilibrium is reached.
66
What happens to a cell in a hypertonic solution?
It shrivels ## Footnote In a hypertonic environment, water exits the cell, leading to cell shrinkage.
67
What happens to a cell in a hypotonic solution?
It bursts ## Footnote A hypotonic solution has a lower solute concentration outside, causing water to enter the cell.
68
What is facilitated diffusion?
Transport proteins help move hydrophilic and charged molecules across the membrane from high to low concentration ## Footnote This process does not require energy and relies on specific transport proteins.
69
What is the Endosymbiont Theory?
A theory explaining the evolutionary origins of mitochondria and chloroplasts ## Footnote The theory suggests that these organelles originated from free-living bacteria that were engulfed by ancestral eukaryotic cells.
70
What are the similarities between mitochondria and bacteria?
* Similar in size * Possess their own DNA * Contain ribosomes similar in size and structure * Antibiotics that do not inhibit protein synthesis in eukaryotes inhibit protein synthesis in bacteria and mitochondria * Enveloped by a double membrane
71
Where does ATP synthesis take place in eukaryotic cells?
In the mitochondria ## Footnote ATP synthesis occurs mainly through the processes of the citric acid cycle and the electron transport chain.
72
What are cristae?
Infoldings of the inner membrane of mitochondria that increase surface area ## Footnote They provide more space for electron transport and reflect the metabolic activity of the cell.
73
Why are mitochondria prevalent in skeletal muscle?
C) Mitochondria provide energy for muscle contraction.
74
What is the primary function of chloroplasts?
Capture light energy for photosynthesis ## Footnote They synthesize sugar using light energy, chlorophyll, and have a double membrane structure.
75
What are thylakoids?
Membranous sacks found in chloroplasts ## Footnote They are organized into stacks called granum.
76
What is the cytoskeleton?
A network of fibers extending through the cell that supports the cell ## Footnote It provides anchorage for organelles and is dynamic, allowing for changes.
77
What are microtubules?
Hollow rods constructed from globular tubulin dimers ## Footnote They support cell shape, guide movement of cellular structures, and separate chromosomes during cell division.
78
What functions do microfilaments serve?
* Involved in cell motility * Muscle contraction * Structural role to bear tension
79
What are intermediate filaments?
More permanent components of the cytoskeleton composed of fibrous keratin molecules ## Footnote They provide higher stability and lower solubility compared to other cytoskeletal elements.
80
Which of the following is not a function of the cytoskeleton?
Passive transport
81
What is the simplest collection of matter that can be alive?
The cell ## Footnote All organisms are made of cells.
82
Who discovered cells in 1665?
Robert Hooke ## Footnote This marked the beginning of cell biology.
83
What type of microscope uses visible light to magnify specimens?
Light microscope (LM) ## Footnote LM can magnify effectively to about 1,000 times.
84
What are organelles?
Membrane-enclosed compartments within cells ## Footnote Most are too small to be resolved by light microscopy.
85
How do electron microscopes (EMs) differ from light microscopes?
EMs use a beam of electrons instead of light ## Footnote This allows for higher resolution.
86
What is a common feature of all cells?
Plasma membrane, cytosol, chromosomes, ribosomes ## Footnote These features are shared among all cells.
87
What type of cells includes bacteria and archaea?
Prokaryotic cells ## Footnote They lack a nucleus and membrane-enclosed organelles.
88
What defines eukaryotic cells?
They have a nucleus and membrane-bound organelles ## Footnote Generally larger than prokaryotic cells.
89
What is the diameter range for prokaryotic cells?
1-5 micrometers ## Footnote Eukaryotic cells are typically 10-100 micrometers.
90
What is the main role of ribosomes?
Protein synthesis ## Footnote Ribosomes can be free in the cytosol or bound to the endoplasmic reticulum.
91
What are the two distinct regions of the endoplasmic reticulum (ER)?
Smooth ER and Rough ER ## Footnote Smooth ER lacks ribosomes, while Rough ER is studded with them.
92
What does the smooth endoplasmic reticulum do?
Synthesizes lipids, metabolizes carbohydrates, detoxifies drugs, stores calcium ions ## Footnote It plays various metabolic roles.
93
What is the function of the Golgi apparatus?
Modifies, manufactures, sorts, and packages materials into transport vesicles ## Footnote It is the shipping and receiving center of the cell.
94
What is anterograde transport?
Movement of material toward the plasma membrane ## Footnote Involves the fusion of secretory granules.
95
What is the primary function of lysosomes?
Digest macromolecules ## Footnote They contain hydrolytic enzymes for this purpose.
96
What process involves lysosomes recycling the cell's own organelles?
Autophagy ## Footnote This process helps maintain cellular health.
97
What type of vacuole is formed by phagocytosis?
Food vacuoles ## Footnote They are involved in the digestion of engulfed material.
98
What is the role of contractile vacuoles?
Pump excess water out of cells ## Footnote Commonly found in freshwater protists.
99
What is the central vacuole's function in plant cells?
Serves as a repository for inorganic ions ## Footnote It may also hold reserves of organic compounds.
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