Chapt 6 Flashcards
Tour of the Cell
1
Q
What device was indispensable for the study of the cell?
A
Light microscope
2
Q
What are the two most important parameters of microscopy?
A
Magnification and Resolving Power
3
Q
The ratio of an object’s image size to its real size is—-
A
Magnification
4
Q
A measure of the clarity of the image is—-
A
Resolving Power
5
Q
What is the maximum resolving power of a light microscope?
A
0.2 um or 200 nm
6
Q
What is the maximum magnification which a light microscope can magnify effectively?
A
1000 times the size of the specimen
7
Q
Define Contrast
A
the difference between adjacent densities or the thing that accentuates different parts of the specimen
8
Q
What can help with contrast in microscopy?
A
Staining or labeling cell components
9
Q
What is a useful technique for studying cell structure and function?
A
Cell fractionation
10
Q
What is the purpose of cell fractionation?
A
It takes cells apart and separates the major organelles and other subcellular structures from one another.
11
Q
What piece of lab equipment is used for cell fractionation?
A
Centrifuge
12
Q
Subcellular structures are called…..
A
Organelles
13
Q
Can organelles be seen by light microscope?
A
No
14
Q
What helped scientists to learn about organelles?
A
Electron microscopy
15
Q
Explain the basic function of electron microscopy.
A
It focuses a beam of electrons through the specimen or onto its surface.
16
Q
How is resolution related to wavelength?
A
Resolution is inversely related to the wavelength of the radiation that a microscope uses for imaging.
17
Q
True or False: Electron beams have longer wavelengths than visible light.
A
False.
18
Q
What’s the maximum resolution of an electron microscope?
A
0.002 nm
19
Q
Which is smaller in size: a mitochondria or virus?
A
Virus (100 nm) is smaller. Mitochandria (1 um)
20
Q
1 nanometer= …..how many micrometers?
A
0.001 um
21
Q
Define Cell Ultrastructure
A
The anatomy of a cell revealed by electron microscope
22
Q
What’s so special about a scanning electron microscope?
A
The electron beam scans the the surface of the sample, coated with gold. The beam excites the electrons on the surface of the specimen. Then, the secondary electrons are detected by a device detects these electrons and sends their pattern via electronic signal to a video screen. This results in a 3D image providing greater depth of field.
23
Q
What type of electron microscopy is used to detect the internal ultrastructure of cells?
A
Transmission Electron Microscope (TEM)
24
Q
How is a specimen prepped for TEM?
A
A thin section of specimen is stained with atoms of heavy metals, which attach to certain cellular structures, thus enhancing electron density of some parts of the cell more than others.
25
Are cells alive or dead when viewing under an electron microscope?
Dead
26
Can cells be alive or dead when viewing under a light microscope?
Can be alive or dead.
27
List 6 types of Light Microcscopy techniques
1. Brightfield 2. Brightfield with stain 3. Phase Contrast 4. Differential interference contrast 5. Fluorescence 6. Confocal
28
What does Phase contrast do?
enhances contrast in unstained specimens
29
What does Differential interference contrast do?
It makes exaggerates the differences in density, making the image appear 3D
30
Does an ultrifuge spin samples at a faster or slower rate than the average centrifuge?
Faster! They spin up to 130,000 RPMs
31
What type of microscope would you use to study living white blood cells?
Light
32
What type of microscope would you use to study the detailed structure of an organelle?
Transmission Electron microscope
33
What type of microscope would you use to study the surface texture of hair?
Scanning Electron microscope
34
How do stains differ between light microscopy and electron microscopy?
Stains for light microscopy are colored molecules that bind to cell components affecting the light passing through it. Electron stains involve heavy metals that affect beams of electrons passing through.
35
A selective barrier common with all cells is called.....
Plasma membrane
36
What is jelly-like substance enclosed by the plasma membrane?
Cytosol
37
Identify parts of the following cell:
Nuclear Pore
Nucleolus
Nuclear Envelope
Centriole
Golgi Apparatus
Cytoplasm
Mitochondria
Rough E.R.
Smooth E.R.
Ribosomes
Lysosomes
38
True for False: A prokaryotic cell lacks a true nucleus
True
39
T or F: All cells contain chromosomes
True
40
T or F: Only animal cells have ribosomes
False
41
What is the function of ribosomes?
To make proteins
42
What's the major difference between prokaryotic and eukaryotic cells?
It's where they store their DNA. For eukaryotic cells it's stored in the nucleus. For prokaryotic cells, the DNA is found in a region which is not membrane-bound called nucleoid.
43
Interior of a prokaryotic cell is called...
Cytoplasm
44
Which cell type is larger, prokaryotic or eukaryotic?
Eukaryotic
45
What are the smallest cells known?
Bacteria, especially mycoplasma
46
General size of most eukaryotic cells
10-100 um
47
What is the purpose of flagella?
Locomotion of organelles of some bacteria
48
Why is the plasma membrane so important?
It allows the sufficient passage of oxygen, nutrients and wastes to service the entire cell.
49
As a cell increases in size, ____ grows proportionately more than \_\_\_\_\_.
Total surace area=
Volume grows proportionately more than its surface area
height x width of all box sides x number of boxes
50
Total volume of cell can be caluculated by...
Surface-to-volume ratio (S-to-V)
Height x widthx length x number of boxes
Surface area/volume
51
Which object would have a greater ratio of surface area to volume? A smaller or larger object?
Smaller object
52
T or F: Larger organsims do not typically have larger cells, they just have more cells.
True
53
Describ why so many cells have long thin shape to them. Give an example.
Longer and thinner shape exposes more surface area to provide for better exchange of materials. Example: intestinal cells have microvilli which increase surface area without increasing volume, allowing maximum materials to be exchanged.
54
Describe the unique structure of a cellular membrane
It consists of a double layer of phospholipids and other lipids. Embedded in this layer are diverse proteins.
55
Animal cells contain what three structures which plants don't have?
Lysosomes
Centrosomes
Flagella
56
Name 4 structures which plant cells have but animal cells do not.
Chloroplasts
Central vacuole
Cell Wall
Plasmodesmata
57
Where is most ATP generated?
Mitochandria
58
What is the function of the lysosome?
It's a digestive organelle where macromolecules are hydrolyzed
59
What is the function of microvilli?
To increase the cell's surface area
60
What is the function of ribosomes?
They make proteins: free proteins in cytosol or bound proteins bound to rough E.R. or bound to nuclear envelope
61
Name 3 parts to the nucleus
Nuclear envelope
Nucleolus
Chromatin
62
\_\_\_\_\_ is a network of membranous sacs and tubes, active in membrane synthesis.
Describe the E.R
Endoplasmic Reticulum (E.R)
E.R. consists of both rough and smooth regions
63
What's the function of the centrosome?
Region of the cell where microtubules are initiated. Contains a pair of centrioles.
64
What is the purpose of the central vacuole in plant cells?
It functions include storage, breakdown of waste products, hydrolysis fo macromolecules
65
Explain function of plasmodesmata
Channels through cell walls that connect the cytoplasms of adjacent cells. (Like little doorways in a house connecting adjacent rooms)
66
What does the chloroplast do?
It is the photosynthetic organelle which converts energy of sunlight to chemical energy stored in sugar molecules
67
The eukaryotic cell's genetic instructions are housed in the ____ and carried out by the \_\_\_
Nucleus. Carried out by the ribosomes
68
T or F: The nuclear membrane is a double membrane.
True. 2 lipid bilayers
69
Discrete units of DNA are housed in \_\_\_
chromosomes
70
Within the chromasome, it is comprised of ___ and \_\_, a complex known as \_\_\_
proteins and DNA, a complex known as chromatin
71
Human cells have how many chromosomes?
What is the only exception?
46
Sex cells which have 23
72
Where does the ribosomal RNA reside?
nucleolus
73
Can there be more than one nuclei?
Yes.
74
Describe the path of protein synthesis in the nucleus.
Nucleus directs protein synthesis by synthesizing messanger RNA (mRNA) according to the instructions from DNA.
The mRNA is then transported to the cytoplasm via nuclear pores.
Once in the cytoplasm, ribosomes translate the mRNA's genetic message into the primary structure of a specific polypeptide.
75
Another name for protein factory
Ribosome
76
Would a cell with a high number of ribosomes also have a high number of nucleoli?
Yes.
77
Free ribosomes are found where?
Bound ribosomes are attached where?
Cytosol
Attached to the outside of the E.R or nuclear envelope
78
What type of proteins do bound ribosomes make?
Free ribosomes mmake what kind of proteins?
Proteins which are destined for insertion into membranes,
Enzymes that catalyze the first steps of sugar breakdown.
79
Name structures which are part of the endomembrane system (5)
E.R.
Golgi apparatus
lysosomes
vacuoles
plasma membrane
80
What is the function of the smooth ER (3)?
Synthesis of lipids
Metabolism of of carbohydrates
detoxification of drugs and poisons
81
Where are the sex hormones of vertebrates produced?
Smooth E.R. (testes and ovaries are rich in smooth ER)
82
Calcium ions are stored in rough or smooth ER?
Why are calcium ions important to muscle?
Smooth
They help trigger the contraction of the muscle cell.
83
Where are drugs detoxified in the body?
Liver. There are plentiful smooth ER in the liver cells
84
Insulin is secreted on the rough ER in _____ cells
Pancreatic cells
85
Most secretory proteins are what kind of specialized protein?
Glycoproteins
86
After leaving the ER, what is the next destination of transport vesicles?
Golgi apparatus
87
The flattened membranous sacs of the Golgi are called\_\_\_\_
cisternae
88
Two different ends of the Golgi are __ and \_\_
Vesicles start at which end and get shipped out at which end?
cis and trans
Vesicles interface with the cis end and get transported to other parts of the cell via trans end.
89
Glycoproteins get modified in which organelle?
Golgi apparatus
90
\_\_\_\_ is a membranous sac of hydrolytic enzymes that an animal cell uses to digest macromolecules.
Lysosomes
91
Lysosomes are happier in a more basic environment, rather than acidic. True or False
False
92
Amoebas eat by engulfing smaller organisms or food particles, process is called \_\_\_
phagocytosis
93
What type of human cell is capable of phagocytosis?
the white blood cell. It defends the body by destroying bacteria and other invaders
94
If the lysosome uses their hydrolytic enzymes to recycle the cell's own organic material, it's called \_\_\_
Autophagy
95
For plants and fungi which lack lysosomes, ___ carry out hydrolysis.
Vacuoles
96
The solution inside a central vacuole in a plant is called \_\_
cell sap
97
\_\_\_ and ____ change energy from one form to another.
Mitochandria in animals
Chloroplst in plants
98
Where is the site of cellular respiration?
Why is cellular respiration important?
mitochandria
It is the metabolic process that generates ATP by extracting energy from sugars , fats, and other fuels with the help of oxygen.
99
Where is the site of photosynthesis?
Chloroplasts
100
Are mitochandria and chloroplasts part of teh endomembrane system?
No.
101
Where are the membrane proteins of mitochandria made?
Do mitochandria contain any DNA?
free ribosomes in the cytosol
Yes, a small amount
102
Peroxisomes imports its proteins from \_\_\_\_
cytosol
103
Are mitochandria found in plant cells?
Yes
104
The higher the metabolic activity of the cell, the higher number of \_\_\_\_\_
mitochandria
105
T or F: the mitochandria do not have a phospholipid bilayer
False
106
Chloroplasts contain the green pigment \_\_\_
chlorophyll
107
T or F: Peroxisomes are bound by a phospholipid bilayer.
What is the function of peroxisomes?
False.
They contain enzymes which transfer hydrogen drom various substrates to oxygen.
108
Which organelle buds from the endomembran system, lysosomes or peroxisomes?
Lysosomes. The peroxisomes increase in number by splitting in 2 when they reach a certain size.
109
What's the role of the plant cytoskeleton?
Support
Mobility
Regulation
110
Name 3 components of the cytoskeleton.
Microtubules
Microfilaments
Intermediate filaments
111
Which component of the cytoskeleton is the thickest?
Which are the thinnest?
Microtubules
Microfilaments
112
Name the protein subunits for each cytoskeleton component:
A. Microtubules
B. Microfilaments
C. Intermediate filaments
A. Tubulin (alpha and beta)
B. Actin
C. Keratin
113
In animal cells, microtubules grow out from a \_\_\_
\_\_\_ are located within the centrosome and occur in pairs
When an animal cell divides, the centrioles \_\_\_\_
centrosome
centrioles
replicate
114
Cilia and Flagella are specialized arrangements of \_\_\_
Which is more numerous...motile cilia or flagella?
Microtubules
Cilia are more numerous. There's usually only one or a few flagella
115
Give a good example of of a cell that uses flagella propulsion for movement.
Give a good example of cilia movement with power stroke/recovery stroke.
Sperm
Freshwater protozoa
116
Microtubules have role in being compression resistan in cells. T or F.
What is the function of microfilaments?
True
To bear tension, pulling forces.
117
T or F: Contraction of a muscle cell results from the actin and myosin filaments sliding past one another.
True.
118
119
120
