The Cell Flashcards

You may prefer our related Brainscape-certified flashcards:
1
Q

Where are all organisms on Earth descended from?

A

They descended from a common prokaryotic ancestral cell about 3.5 billion years ago.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Theory of Endosymbiosis

A

About 1.5 billion years ago. Eukaryotic cells emerged when mitochondria and chloroplasts, once free-living prokaryotes, took up permanent residence inside larger cells.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Eukaryotic Cell

A

Complex cell with nucleus and internal membranes that compartmentalize the cell. They led to the evolution of multi-celled organisms. They make up every other form of life.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Cell Size

A

10-100 micrometers; human red blood cells are about 8 micrometers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Cell Theory: Schleiden and Schwann

A

All living things are composed of cells; Cells are the basic unit of all organisms; All cells arise from preexisting cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Cells in General

A

Cells are enclosed by a membrane that regulates the passage of material between the cell and tis surrounding. They also contain nucleic acid which directs the cell’s activities and controls inheritance.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Prokayotic Cells

A

Have no nucleus or other internal organs.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Eukaryotic Cell

A

Complex cell with nucleus and internal membranes that compartmentalize the cell. They led to the evolution of multi-celled organisms. DNA wrapped with histone proteins into chromosomes, ribosomes are larger, metabolism is aerobic, cytoskeleton present, mainly multicellular with differentiation and cells are larger.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Prokayotic Cells

A

Have no nucleus or other internal organs. Circular, naked DNA. Ribosomes are small, metabolism in anaerobic/aerobic, cytoskeleton is absent, mainly unicellular and cells are very small.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Prokayotic Cells

A

Have no nucleus or other internal organs. Circular, naked DNA. Ribosomes are small, metabolism in anaerobic/aerobic, cytoskeleton is absent, mainly unicellular and cells are very small.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Microscopes

A

Main tool for studying cells. They magnify an image over 100,000 times. Resolution, high magnification and high resolution are characteristics of a good microscope.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Microscrope: Resolution

A

clarity of the image

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Microscopes and People to Know

A

Antoine van Leeuwenhoek developed the first microscope and Robert Hooke advanced it which enabled him to study and name cells in a cork.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Microscopes and People to Know

A

Antoine van Leeuwenhoek developed the first microscope and Robert Hooke advanced it which enabled him to study and name cells in a cork.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Light Microscopes

A

Microscopes that use light passing through a living/dead specimen to form an image. Cells/tissue can be staines to make organelles easier to see however stains may kill cells.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Electron Microscopes

A

Microscopes that use electrons passing through a specimen to form an image. They have superior revolve and magnification power. However, they cannot be used to view live specimens because the specimen preparation kills the cells.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Transmission Electron Microscopes

A

Used to study the interiors of cells. The images appear flat and 2D. The tissues must be cut into very small pieces and exposed to a fixative that stops all biochemical activity. The tissue is then dehydrated, embedded in a polymer, cured overnight and sliced on an ultramicrotome.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Scanning Electron Microscopes

A

Used to study the surface of cells. The images appear 3D. Specimens are coated with a heavy metal such as gold and are placed directly on the microscopes for observing. Specimens are not alive.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Phase-Contrast Microscopes

A

Used to examine unstained, living cells. It is often used to examine cells growing in tissue culture.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Phase-Contrast Microscopes

A

Used to examine unstained, living cells. It is often used to examine cells growing in tissue culture.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Cell Fractionation

A

Using an ultracentrifuge to spin liquids at high speeds and separate them based on differences in density. Tissues/cells are first mashed up in a blender to form a homogenate. The most dense particles such as nuclei are pushed to the bottom, followed by mitochondria and ribosomes. The supernatant, liquid above the pellet, can be poured off an re-spun.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Cell Fractionation

A

Using an ultracentrifuge to spin liquids at high speeds and separate them based on differences in density. Tissues/cells are first mashed up in a blender to form a homogenate. The most dense particles such as nuclei are pushed to the bottom, followed by mitochondria and ribosomes. The supernatant, liquid above the pellet, can be poured off an re-spun.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Freeze Fracture and Freeze-Etching

A

Multistep techniques used to prepare a detailed cast of the membrane. The tissue is then digested away leaving only the cast which can be examined under the electron microscope.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Tissue Culture

A

Used to study the properties of specific cells in vitro. Cell lines can be grown in culture for years and while the cells are growing they can be studied with a phase-contrast microscope.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Tissue Culture

A

Used to study the properties of specific cells in vitro. Cell lines can be grown in culture for years and while the cells are growing they can be studied with a phase-contrast microscope.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Tissue Culture

A

Used to study the properties of specific cells in vitro. Cell lines can be grown in culture for years and while the cells are growing they can be studied with a phase-contrast microscope.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Nucleus

A

Contains chromosomes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Nucleus

A

Contains chromosomes which are wrapped with special proteins into a chromatin network. It’s surrounded by a selectively permeable membrane or envelope that contains pores to allow for the transport of molecules which are too large to diffuse directly through the envelope.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Nucleolus

A

An interphase in the nucleus contains this region where components of ribosomes are synthesized. 1 to 2 nucleoli may be visible. Nucleoli are not membrane-bound structures but are actually a tangle of chromatin and unfinished ribosome precursors.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Ribosomes

A

The site of protein synthesis. They can be found free in the cytoplasm or attached to the endoplasmic reticulum.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Endoplasmic Reticulum

A

A membranous system of channels and flattened sac that traverse the cytoplasm.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Rough ER

A

The site of protein synthesis resulting from the attached ribosomes.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

Smooth ER

A

Assists in the synthesis of steroid hormones and other lipids; connects rough ER to the Golgi apparatus; Carrier out various detoxification processes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

Golgi Apparatus

A

Lies near the nucleus and consists of flattened membraneous sacs stacked net to one another and surrounded by vesicles. They package substances produced in the rough ER and secrete them to other cell parts or the cell surface for export.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

Golgi Apparatus

A

Lies near the nucleus and consists of flattened membraneous sacs stacked net to one another and surrounded by vesicles. They package substances produced in the rough ER and secrete them to other cell parts or the cell surface for export.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

Lysosomes

A

Sacs of hydrolytic (digestive) enzymes surrounded by a single membrane. They are a site of intracellular digestion. The cells can continually renew itself by breaking down and recycling its parts. Apoptosis occurs with a cell’s own hydrolytic enzymes which is essential for multi-celled organisms.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

Peroxisomes

A

Found in both plant and animal cells. They contain catalase which converts hydrogen peroxide (waste product of cellular respiration) into water with the release of oxygen atoms. They also detoxify alcohol in liver cells.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

Mitochondria

A

The site of cellular respiration. All cells have them but a very active cells could have 2,000+. They have an outer double membrane and an inner series of membranes called cristae. They contain their own DNA.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

Vacuoles

A

Single, membrane-bound structure for storage. Vesicles are smaller version of these. Contractile vesicles pump out extra water; they’re found in freshwater protista.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

Plastids

A

Only found in plants and algae. Have a double membrane.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

Plastids: Chloroplasts

A

Site of photosynthesis. In addition to the double outer membrane so they have an inner one that forms a series of structure called grana. The grana consist of thylakoids and lie in the stroma. They contain their own DNA.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

Plastids: Leucoplasts

A

Store starch and are found in roots like turnips or in tubers like the potato.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

Plastids: Chromoplasts

A

Store carotenoid pigments and are responsible for the red-orange-yellow of carrots, tomatoes and daffodils.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

Cytoskeleton

A

Complex network of protein filaments that extend through the cytoplasm and gives the cell its shape and enables it to move. It also anchors organelles to the plasma membrane.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

Cytoskeleton: Microtubules

A

Hollow tubes made of the protein tubulin that make up the cilia, flagella, and spindle fibers. Cilia and Flagella help with locomotion. Spindle fibers help to separate chromosomes during meiosis and mitosis.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

Spindle Fibers: Structure

A

Microtubules organized into 9 triplets with no microtubules in the center.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

Cytoskeleton: Microfilaments/Actin Filaments

A

Help support the shape of the cell. They enable animal cells to form a cleavage furrow during cell division; amoebas to move by sending out pseudopods; and skeletal muscle to contract at they slide myosin filaments.

48
Q

Centrioles, Centrosomes or Microtubules Organizing Centers

A

Non-membranous structure that lie outside the nuclear membranes. They organize spindle fibers and give rise to the spindle apparatus required for cell division. Two centrioles oriented at right angles to each other make up one centrosome and consists of 9 triplets of microtubules arranged in a circle. Plants lack centrosomes but have MTOCs.

49
Q

The Cell Wall

A

Not found in animal cells. The primary cell wall is immediately outside of the plasma membrane. Some cells have a secondary cell wall outside the primary cell wall. When a cell divides a thin gluey layer is formed which becomes the middle lamella.

50
Q

Cell Wall: Structure

A

Plants and algae have cell walls made out of cellulose. The cell walls of fungi are usually made of chitin. The average membrane is the consistency of olive oil and is 40% lipid and 60% protein.

51
Q

Fluid Mosaic Model

A

S.J.Singer’s description of the cell membrane. The eukaryotic plasma membrane consists of a phospholipid bilayer with proteins dispersed through the layers. Phospholipids move along the plane of the membrane rapidly while some proteins are kept in place by attachment to the cytoskeleton.

52
Q

Amphiphatic

A

A characteristic of phospholipids. This means it has both a hydrophilic and hydrophobic regions.

53
Q

Integral Proteins

A

Proteins that have non-polar regions that completely span the hydrophobic interior of the plasma membrane.

54
Q

Peripheral Proteins

A

Proteins that are loosely bound to the surface of the plasma membrane.

55
Q

Cholesterol Molecules

A

Molecules embedded in the interior of the bilayer to stabilize the membrane.

56
Q

Glycocalyx

A

The external surface of the plasma membrane also has carbohydrates attached to it. This is important of cell to cell recognition.

57
Q

Glycocalyx

A

The external surface of the plasma membrane also has carbohydrates attached to it. This is important of cell to cell recognition.

58
Q

Plasma Membrane: Proteins as Transport Molecules

A

They transport ions, molecules, and electrons through channels, pumps, carriers and electron transport chains.

59
Q

Plasma Membrane: Proteins as Enzymes

A

Ex. One membrane-bound enzyme located within the cell membrane that synthesizes cyclic AMP (c-AMP) from ATP is adenylate cyclase.

60
Q

Plasma Membrane: Proteins as Receptors

A

They act as receptors for hormones, neurotransmitters, receptor-mediated endocytosis, and for cells of the immune system.

61
Q

Plasma Membrane: Proteins in Cell to Cell Attachment

A

Ex. Desmosomes serve as anchors for filaments and river cells together.

62
Q

Cell Transport

A

Movement of substances into and out of a cell. Either active which requires energy (ATP) or passive which requires no energy.

63
Q

Passive Transport

A

Movement of molecules down a concentration gradient from a region of high concentration to a region of low concentration. Ex. diffusion and osmosis

64
Q

Diffusion: Simple

A

Does not involve protein channels. Ex. in the glomerulus of the human kidney, where solutes dissolved in the blood diffuse into Bowman’s capsule of the nephron.

65
Q

Diffusion: Facilitated

A

Required hydrophilic protein channels that will passively transport substances. Ex. one channel transports single ions.

66
Q

Countercurrent Exchange

A

The flow of adjacent fluids in opposite direction that maximizes the rate of simple diffusion.

67
Q

Countercurrent Exchange: Fish Gills

A

Blood flows toward the head in the gills while water flows over the gills in the opposite direction. This maximizes the diffusion of respiratory gases and wastes between the water and the fish.

68
Q

Countercurrent Exchange: Fish Gills

A

Blood flows toward the head in the gills while water flows over the gills in the opposite direction. This maximizes the diffusion of respiratory gases and wastes between the water and the fish.

69
Q

Osmosis

A

Term for diffusion of water across a membrane.

70
Q

Solvent

A

Substance that does the dissolving.

71
Q

Solute

A

Substance that dissolves

72
Q

Hypertonic

A

Having greater concentration of solute that another solution.

73
Q

Hypotonic

A

Having lesser concentration of solute than another solution.

74
Q

Isotonic

A

Two solutions containing equal concentration of solutes.

75
Q

Osmotic Potential

A

The tendency of water to move across a permeable membrane into a solution.

76
Q

Water Potential

A

Movement of water. Results from two factors: solute concentration and pressure. Water potential for pure water is zero. The addition of solutes lowers water potential to a value less than zero. Water will move across a membrane from the solution with higher water potential to a solute with lower water potential.

77
Q

Water Potential Values

A

Water potential for pure water is zero. The addition of solutes lowers water potential to a value less than zero. Water potential inside a cell is a negative value.

78
Q

Water Potential Values

A

Water potential for pure water is zero. The addition of solutes lowers water potential to a value less than zero. Water potential inside a cell is a negative value.

79
Q

Hypotonic Solution

A

The concentration of solute in the beaker is less than the concentration of solute in the cell. Water will flow into the cell causing the cell to swell.

80
Q

Turgid

A

A cell that is swelled. What keeps plant crisp. If a plant cell dehydrates it will lose turgor pressure and wilt.

81
Q

Hypertonic Solution

A

The concentration of solute in the beaker is greater than the concentration of solute in the cell. Water will flow out of the cell from high concentration of water to low concentration of water.

82
Q

Plasmolysis

A

A cell that shrinks due to flow of water out of the cell.

83
Q

Plasmolysis

A

A cell that shrinks due to flow of water out of the cell.

84
Q

Aquaporins

A

Specialized water channel proteins that facilitate the diffusion of massive amounts of water across a cell membrane. They don’t affect the water potential gradient or the direction of water flow but affect the rate at which water diffuses down its gradient.

85
Q

Aquaporins as Gated Channels

A

Gates that open and close in response to changes in tonicity. A sudden change in a cell in response to changes in tonicity may be results of aquaporins.

86
Q

Aquaporins as Gated Channels

A

Gates that open and close in response to changes in tonicity. A sudden change in a cell in response to changes in tonicity may be results of aquaporins.

87
Q

Active Transport

A

The movement of molecules against a gradient which requires energy (ATP). Examples are pumps or carriers that carry particles across the membrane by active transport.

88
Q

Plastoquinone

A

Active transport occurs in the thylakoid membrane of chloroplasts by this mobile electron carrier.

89
Q

Sodium-Potassium Pump

A

Pumps Na+ and K+ ions across a nerve cell membrane to return the nerve to resting state. They move against a gradient. Two K+ ions for very three Na+ ions.

90
Q

Electron Transport Chain

A

Active transport in mitochondria consists of proteins that pump protons across the cristae membrane.

91
Q

Contractile Vacuole

A

In freshwater Protista this pumps out excess water that has diffused inward because the cell lives in a hypotonic environment.

92
Q

Exocytosis

A

Active transport occurs in nerve cells as vesicles release neurotransmitters into a synapse.

93
Q

Pinocytosis

A

Active transport in the uptake of large, dissolved particles. (AKA cell drinking). The plasma membrane invaginated around the particles and encloses them in a vesicle.

94
Q

Phagocytosis

A

The engulfing of large particles or small cells pseudopods. The cell membrane wraps around the particle and encloses it into a vacuole. This is the way white blood cells engulf bacteria.

95
Q

Receptor-Mediated Endocytosis

A

Enables a cell to take up large quantities of a specific substance through active transport. It is a process by which extracellular substances bind to receptors on the cell membrane.

96
Q

Receptor-Mediated Endocytosis Process

A

Once a ligand binds to the receptors, endocytosis begins. The receptors, carrying the ligand, migrate and cluster along the membrane. The receptors turn inward and become coated vesicles that enter the cell. Ex. How cholesterol is taken in from the blood.

97
Q

Ligan Define

A

Any molecule that bind specifically to a receptor site of another molecule.

98
Q

Ligan Define

A

Any molecule that bind specifically to a receptor site of another molecule.

99
Q

Bulk Flow

A

Term for the overall movement of a fluid in one direction in a organism. Bulk flow movement is always from source to sink.

100
Q

Bulk Flow: Blood

A

In humans blood moves around the body by bulk flow as a results of blood pressure created by the pumping heart.

101
Q

Bulk Flow: Sap

A

Sap in trees moves by bulk flow from the leaves to the roots due to active transport in the phloem.

102
Q

Glycocalyx

A

The external surface of the plasma membrane also has carbohydrates attached to it. This is important of cell to cell recognition.

103
Q

Bulk Flow: Sap

A

Sap in trees moves by bulk flow from the leaves to the roots due to active transport in the phloem.

104
Q

Cell Communication

A

In multi-celled organisms individual cells work together through cell junctions, signal transduction pathway, and cell-to-cell recognition.

105
Q

Cell Junction: Tight Junctions

A

Belts around epithelial cells that line organs and serve as a barrier to prevent leakage into/out of those organs. In the urinary bladder, they prevent urine from leaking out the bladder to the surrounding body cavity.

106
Q

Cell Junction: Desmosomes

A

They are found in many tissues and have been compared to spot welds that rivet cells together. They consist of clusters of cytoskeleton filaments looped together. They occur in tissues that are subjected to mechanical stress such as skin epithelium or neck of the uterus.

107
Q

Cell Junction: Gap Junction

A

Permit the passage of materials from the cytoplasm of one cell to the cytoplasm of an adjacent cell. In the middle tissue of the heart, the flow of ions through the gap junctions coordinate the contraction of the cardiac cells.

108
Q

Cell Junction: Plasmodesmata

A

Connect one plant cell to the next and are similar to gap junctions in animal cells.

109
Q

Signal Transduction Pathway

A

It relied on plasma membrane proteins in a multistep process in which a small number of extracellular signal molecules produce a major cellular response.

110
Q

Three Stages of Cell Signaling

A

Reception, Transduction, and Response

111
Q

Signal Transduction Pathway: Reception

A

Signal molecules (usually a protein that doesn’t enter the cell) binds to a specific receptor on the cell surface causing the receptor molecule to change in conformation.

112
Q

Signal Transduction Pathway: Transduction

A

After the change in the cell surface receptor this leads to transduction. This is a change in signal form where the receptor relays a messages to a secondary messenger.

113
Q

Signal Transduction Pathway: Response

A

After transduction, the secondary signaling molecule gets the message, it induces a response within the cell.

114
Q

Cell-to Cell Recognition

A

The cell’s ability to distinguish one type of neighboring cell from another is crucial to the function of multi-celled organism. The glycocalyx is a feature that aids in this.

115
Q

Cell-to-Cell Recognition: Glycocalyx

A

Consists of oligosaccharides (small chains of sugar molecules) attached to integral proteins within the plasma membrane. This is responsible for a phenomenon called contact inhibition.

116
Q

Contact Inhibition

A

Caused by glycocalyx which causes the normal trait of cells to stop dividing when they become too crowded.