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bio 215 summer > chapter 4 cells/organelles > Flashcards

chapter 4 cells/organelles Flashcards

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1
Q

What were the four phases of the appearance of cells?

A

1) Abiotic (nonliving) synthesis of simple organic compounds
2) Abiotic polymerization of these into macromolecules
3) Emergence of a macromolecule capable of replication and storing genetic information
4) Encapsulation of the first living molecule within a simple membrane

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2
Q

What was the Stanley Miller experiment and what did it prove?

A

Miller tested the hypothesis that energy from lightning could have powered the production of simple organic compounds from atmospheric gases.

Results: He detected two simple amino acids (alanine and glycine) in the flask.

Suggested that some organic compounds could be produced under abiotic conditions.

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3
Q

What was the first informational molecule?

A

RNA

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4
Q

Deoxyribonucleic acids, used to form DNA, are derived _____ from the corresponding ribonucleotides.

A

enzymatically

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5
Q

RNAs called _____ are capable of performing certain enzymatic reactions; for example, the formation of the peptide bonds during translation.

A

ribozymes

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6
Q

What may have been the first primitive protocells?

A

Liposomes

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7
Q

Using lipids, scientists have produced hollow, membrane bound vesicles called

A

liposomes

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8
Q

What was the theory behind liposomes?

A

Under some circumstances, these can carry out simple metabolic reactions. Primordial lipids may have come together in an early ocean, trapping RNAs and forming the first “protocells.”

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9
Q

What is the difference between eukaryotic and prokaryotic?

A

Eukaryotic cells (plants, animals, fungi, algae, and protozoa) have a membrane bounded nucleus

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10
Q

What are the two types of prokaryotic cells?

A

Bacteria and Archaea

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11
Q

Bacteria

A

include most of the commonly encountered single celled, non nucleated organisms

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12
Q

archaea

A

live in weird, extreme habitats and have diverse metabolic strategies

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13
Q

Why should cells have a high surface area to volume ratio?

A

SA is important because exchanges between the cell and its surroundings take place at the cell surface. The cell’s volume determines the amount of exchange that must take place across the available SA .

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14
Q

Cells that are specialized for absorption have characteristics to maxamize ___ ___

A

Surface Area

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15
Q

What is special about the intestine?

A

The crevices give time for nutrients to stay in and cells to absorb. Gives time for absorption

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16
Q

Many molecules move through the cytosol by

A

diffusion

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17
Q

The rate of diffusion of molecules ____ as the size of the molecule increases

A

decreases

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18
Q

Eukaryotic cells can avoid the problem of slow diffusion rates by using what?

A

carrier proteins

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19
Q

A eukaryotic cell has a true, membrane-bounded nucleus, what do bacterial or archael cells have?

A

Nucleoids that are attached the cell membrane

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20
Q

Some bacteria have membrane bound or protein lined structures that serve (or resemble) organelles. Does this mean they have organelles?

A

NO

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21
Q

Bacterial DNA is present in the cell as a ____ molecule, called a ____, associated with few proteins.

A

circular; chromosome

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22
Q

Eukaryotic DNA is organized into ___ molecules complexed with large amounts of proteins called ____.

A

linear; histones

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23
Q

Archaeal DNA is ___ and complexed with proteins similar to eukaryotic ___ proteins

A

circular; histone

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24
Q

How is the problem of DNA packaging solved among eukaryotes?

A

DNA is organzied into chromosomes

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25
Bacterial and archaeal cells replicate their D N A and divide by ____ _____, with one molecule of the replicated D N A and the cytoplasm going into each daughter cell.
binary fission
26
Eukaryotic cells replicate D N A and then distribute their chromosomes into ___ ___ by mitosis and meiosis, followed by cytokinesis, division of the cytoplasm.
daughter cells
27
Eukaryotic cells _____ genetic information in the nucleus into large RNA molecules that are processed and transported into the cytoplasm for protein synthesis.
transcribe
28
# Each mature RNA molecule typically encodes one ----
polypeptide
29
Bacteria transcribe genetic information into RNA, and the R N A molecules produced may contain information for ....
several polypeptides.
30
Is there a lot of RNA processing in bacteria?
NO
31
In archaea, there is a ____amount of RNA processing.
moderate
32
In both bacteria and archaea, RNA molecules become ...
involved in protein synthesis before transcription is complete.
33
Plasma Membrane
-defines cell boundaries and retains contents -consists of lipids, including phospholipids and membrane proteins, and is organized into two layers
34
Nucleus
-the information center of the eukaryotic cell -contains the DNA and is surrounded by the nuclear envelope composed of inner and outer membranes
35
The _____ _____ has numerous openings called pores, each of which is a transport channel lined with a nuclear pore complex.
nuclear envelope
36
Chromosomes are most easily visualized during mitosis, whereas during interphase they are dispersed as _____ and difficult to visualize.
chromatin
37
Nucleoli
are responsible for synthesizing ribosomal RNA and beginning the assembly of proteins
38
Mitochondria
It contains enzymes and intermediates needed for oxidation of sugars and generation of adenosine triphosphate (ATP).
39
chloroplast
harvest solar energy and converts it to chemical energy in the form of ATP
40
______, found in all eukaryotic cells, are the site of aerobic respiration.
Mitochondria
41
The inner mitochondrial membrane encloses the ____, a semifluid material filling the mitochondria.
matrix
42
cristae
infoldings of the mitochondrial membrane
43
Chloroplasts are surrounded by both inner and outer membranes and contain a system of flattened membranous sacs called ____, stacked into grana
thylakoids (interconnected by stroma thylakoids)
44
stroma
a semifluid in the interior of the chloroplast
45
Plastids
Class of plant organelles
46
Chromoplasts
are pigment-containing plastids responsible for the coloration of flowers, fruits, and other plant parts
47
Amyloplasts
are specialized for the storage of starches
48
Mitochondria and chloroplasts are_______ organelles, with many similarities to bacteria
semiautonomous
49
Semiautonomous organelles can
divide on their own and contain their own DNA, mRNA, tRNAs, and ribosomes.
50
THE ENDOSYMBIONT THEORY
suggests that mitochondria and chloroplasts evolved from ancient bacteria that established a symbiotic relationship with primitive nucleated cells
51
evidence of the endosymbiont theory
* Mitochondria and chloroplasts have a double membrane (like bacteria). * The membranes have bacteria-like lipids and transmembrane proteins.
52
The first step toward evolution of mitochondria may have occurred when an _____ protoeukaryote ingested smaller _____ bacteria by phagocytosis.
anaerobic; aerobic
53
The endomembrane system
synthesizes proteins destined for various organelles, cellular membranes, or secretion
54
Endoplasmic reticulum
a network of membranes in the cytoplasm
55
cisternae
tubular membranes and flattened sacs on the ER
56
lumen
The internal space of the ER
57
Rough ER
studded with ribosomes on the cytoplasmic side of the membrane
58
What do the ribosomes from the RER do?
synthesize polypeptides that accumulate within the membrane or are transported across it to the lumen
59
Smooth ER
has no role in protein synthesis. It is involved with the synthesis of lipids and steroids such as cholesterol and its derivatives.
60
____ is responsible for inactivating and detoxifying potentially harmful substances.
Smooth ER
61
Golgi apparatus
It plays an important role in processing and packaging secretory proteins, and in synthesis of complex polysaccharides. * It accepts transition vesicles that bud off the ER.
62
Once processed by the Golgi complex, materials to be exported from the cell are packaged into
secretory vesicles.
63
What makes up the endomembrane system?
The ER, Golgi, secretory vesicles, and lysosomes
64
Ribosomes
are the site of protein synthesis and are far more numerous than most other intracellular structures
65
Sedimentation coefficient
a measure of how rapidly a particle sediments in an ultracentrifuge, expressed in Svedberg units (S). * Ribosomes have values of 80S (eukaryotes) or 70S (bacteria and archaea).
66
How many subunites do ribosomes have and what are they?
2; large and small
67
Lysosomes
are single-membrane organelles that store hydrolases, enzymes that can digest biological molecules
68
____ are sequestered to prevent them from digesting the contents of the cell
hydrolases
69
peroxisome
involved in breaking down fatty acids, detoxifying harmful substances like hydrogen peroxide, and participating in lipid metabolism and immune signaling.
70
peroxisome in animals
In animals, they play roles in oxidative breakdown of fatty acids, especially longer-chain fatty acids (up to 22 carbon atoms).
71
peroxisome in plants
During germination of fat-storing seeds, specialized peroxisomes called glyoxysomes play a role in converting the stored fat into carbohydrates.
72
cytoskeleton
provides structure to the cytoplasm
73
The three structural elements of the cytoskeleton
microtubules, microfilaments, intermediate filaments
74
For many animal cells, these structures are called the extracellular matrix (ECM) and consist mainly of
collagen fibrils and proteoglycans
74
For plant and fungal cells, the extracellular structures are ____ and consist of _____ ____
cell walls; cellulose microfibrils
75
The primary cell wall
is laid down during cell division and consists mainly of cellulose fibrils embedded in a polysaccharide matrix it is flexible
76
The secondary cell wall
forms when the plant cell reaches full size by deposition of additional cellulose and lignin on the inner surface of the primary cell wall. * It is rigid and inextensible.
77
Bacterial cell walls are composed of...
peptidoglycans
78
* Plant cells are ____ and thus suited to the rigidity that cell walls confer on an organism. * Animal cells are ____ and therefore are surrounded by a strong but elastic network of collagen fibers. * Bacteria and archaea may be ____; their cell walls provide protection from bursting due to osmotic differences between the cell and the surrounding environment.
nonmotile; motile; motile or not
79
Viruses
are acellular parasitic particles incapable of a free-living existence.
80
Viruses have no ____; _____ or _____- and consist of only a few different molecules of nucleic acid and protein.
cytoplasm, organelles, or ribosomes
81
Viruses are chemically quite simple, consisting of a
coat (capsid) of protein surrounding a core containing D N A or R N A, depending on the type of virus.
82
Some viruses are surrounded by a membrane and are called
enveloped viruses
83
Which do viruses not satisfy? - Metabolism (cellular reactions, in pathways) * Irritability (perception of and response to external stimuli) * Ability to reproduce
the first two
84
Viroids
ARE SMALL, CIRCULAR RNA MOLECULES THAT CAN CAUSE PLANT DISEASES
85
PRIONS
are proteinaceous infective particles that are responsible for neurological diseases such as scrapie, kuru, Creutzfeldt-Jakob and mad cow disease Prions are abnormally folded versions of normal cellular proteins. * Prions cannot be destroyed by cooking or boiling.
86

bio 215 summer (8 decks)

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