Human Biology > Chapter 3 > Flashcards

Chapter 3 Flashcards

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1
Q

The cell theory: three steps

A

1) a cell is the basic unit of life
2) all living things are composed of cells
3) all cells come from preexisting cells

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2
Q

How are cells classified

A

Cells are classified according to their internal organization

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3
Q

What are composite cells created for

A

They are created for the purposes of studying only

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4
Q

A typical cell is what

A

Composite cell - a cellular model that exhibits the most important characteristic

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5
Q

The three main structures of a cell and a description

A

1) nucleus - this is the control center or central processing station for the cell
2) cytoplasm - cytosol (intercellular fluid) -> has organelles
3) plasma membrane - this is inside the extra cellular

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6
Q

What does a nucleus contain

A
  • contains genetic info of a cell, and controls all activity
  • DNA contains the master code for making RNA and proteins/enzymes
  • therefore, the DNA dictates the function of the cell
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7
Q

What is the structural function of a nucleus

A
  • double layered nuclear membrane
  • nuclear pores
  • chromosomes/chromatin
  • nucleolus -> contains RNA
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8
Q

What is a nucleolus

A

A nucleolus synthesizes RNA, which in turn combines with protein to create ribosomes, which can also synthesize proteins

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9
Q

Define cytoplasm

A

A gel-lik substance of cells that contain many tiny suspended structures

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10
Q

Define cytosol

A

“Little organs,” membranous, non-membranous

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11
Q

Define and explain ribosomes

A

They are called protein factories and are the site that the protein synthesis will happen at. The ribosomes in turn create many “enzymes” which are structural and functional proteins.

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12
Q

Where are ribosomes:
Free and bound

A
  • Ribosomes are free floating in cytoplasm, attached to the outer surface of the endoplasmic reticulum.
    Free ribosome - synthesizes proteins for the cells immediate use
    Bound ribosome - synthesizes proteins to be transported immediately to organelles or exported from the cell.
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13
Q

Endoplasmic reticulum is considered what in the human body

A

the endoplasmic reticulum is considered the “manufacturing center” in the human body

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14
Q

Explain the difference between rough and smooth endoplasmic reticulum (ER)

A

Rough: has ribosomes, and manufactures proteins
Smooth: no ribosomes, manufactures lipids, then prepares these proteins and lipids for the Golgi apparatus

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15
Q

What is the Golgi apparatus and what does it do?

A

The Golgi apparatus is considered the “Processing and packaging plant” in the human body.
- refines synthesized products
- is the packaging and shipping center
- is packed into vesicles and shipped to different cell locations or cell membranes to export

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16
Q

What are vesicles and what are the four types

A

A vesicle is a membrane-bound storage and shipping containers.
1) secretory -> contain products to be exported from the cell
2) endocytic -> contains substances that are exported externally
3) peroxisomes -> contain enzymes that detoxify wastes produced by the cell
4) lysosomes -> contain digestive enzymes

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17
Q

Define cytoskeleton and its organelles

A

Cytoskeleton - internal scaffolding, that helps maintain the cells shape. The basic cytoskeleton organelles are; cell fibers, centrosome, molecular motors, cell extensions

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18
Q

Define cell fibers

A

Cell fibers are the cytoskeleton which also support and anchors the other cellular structures in the body.

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19
Q

Define microtubules

A

Microtubules are tiny hollow tubes of protein

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20
Q

Define microfilaments

A

Microfilaments are thin solid fibers of protein

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21
Q

Microtubules and microfilaments do what for the cell

A

They for the basic framework to provide support for the cell

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22
Q

What is a centrosome and what is its important role

A

A centrosome is the “microtubule - organizing center” and is a non-membranous structure in the cell.
A centrosome is important in the role of cell division

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23
Q

Define pericentriolar material

A

Pericentriolar material is a cloud like mass of material surrounding centrioles, active to help new growth of new microtubules

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24
Q

What is the description of mitochondria

A
  • “Powerhouse of the cell”
    The primary purpose is the synthesis of ATP
  • cellular respiration and utilizes O2 and produces CO2
  • the number of mitochondria varies based on the energy requirements of the cell
  • surrounded by a double membrane, and inner one is highly folded
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25
Cell extensions are what and are classified as?
Cell extensions are projections that extend plasma membranes outward to form tiny, fingerlike processes Microvilli - increases the surface area to assist in secretion and absorption Cilia - assist with movement along the cell surface Flagella - assists with movement of the cell itself (Ie: Sperm)
26
Plasma membranes are what? Phospholipids Cholesterol Carbohydrates Proteins
Plasma membranes are a lipid belayer, that is non-rigid, and is a fluid mosaic Phospholipids- have a polar head and a non-polar tail Cholesterol - makes the membrane more rigid Carbohydrates - recognition of patterns for the cells and organisms Proteins - provide means of transport through membranes
27
Cell connections are what - Desmosomes Gap junctions Tight junctions
Desmosomes - permit some movement between the cells, and allow tissues to stretch and bend. (Example is skin) Gap junctions - protein channels that enable movement of the membranes between cells. (Example is live, and heart) Tight junctions - they seal plasma membranes tightly together (example would be digestive tract lining and the bladders lining)
28
Cell function is
Cell function - in order for cells to function and survive, we need to be able to move substances where they re needed and can be utilized. This can mean getting info through the phospholipid belayer of the cell membrane ————
29
The types of cell function are?
Passive -> this does not require any energy expenditure or “activity” of the membrane. these particles move by using the energy that they already have. Active -> requires expenditure of metabolic energy by the cell, and particles are actively pulled across the membrane. Diffusion -> refers to the spread out evenly in any given space - ———— Concentration gradient -> a measurable difference in concentration from one are to another.
30
What will molecules always do with a concentration gradient
Molecule will ALWAYS spread down the concentration gradient
31
Define osmosis:
The diffusion of water across a selectively permeable membrane
32
define osmotic pressure
Fluid pressure required to exactly oppose osmosis.
33
What does diffusion refer to?
Diffusion refers to a natural phenomenon caused by the tendency of small particle to spread out evenly within any given space
34
Explain how diffusion works
Diffusion happens directly through the lipid bilayer - through small uncharged nonpolar molecules (O2, CO2, Urea) Diffusion happens through the protein channels in the bilayer - some are always open, other get “gated” (H2O, ions) Important note: Always in relation to solutes Facilitated diffusion - this is what facilitates transportation - when this happens the membrane transport protein changes shape and transports molecules through the bilayer. This is tightly specific (glucose)
35
Active transport by vesicles
Endocytes: the plasma membrane “traps” some extra cellular material and brings it into the cells. (This could be cause by cytoskeleton, receptor-mediated endocytosis) - phagocytes “cell drinking” similar processes found in which fluid and the substances dissolved in it will enter the cell. (solutes) - pinocytes “cell eating” microorganisms are engulfed by the plasma membrane and enter the cell in vesicles that have been pinches off by the membrane and then digested. (solvents)
36
Cell function described
Integral proteins serve an important role in the everyday function of the cell. Anatomy will always dictate physiology - for example, information can be transferred across the PM and sodium potassium pump maintaining cell volume.
37
What does an increase and decrease in cell volume do?
An increase in cell volume means there is more water in the cytoplasm which decreases pumping and allows more sodium inside the cell A decrease in cell volume means there is less water in the cytoplasm, which in turn increase pumping and expels sodium ions from the cell
38
What type of pumps expel and stockpile? What does ATP do?
NaK -> this pump expels unwanted ions Na+ ->this pump stockpiles needed ones K+ -> maintains the cell volume ATP is used to expel three Na+ for every 2 K+ that get brought into the cell
39
Isotonic extracellular fluid also maintains cell volume and how?
Toxicity - the relative concentration of solutes in two fluids. Isotonic - extracellular and I trace lunar solute concentrations are equal throughout. - cells work to maintain a normal volume in isotonic extracellular fluids - regulatory mechanisms maintain extracellular fluid that is isotonic with intracellular fluid
40
Hypertonic vs. Hypotonic
Hypertonic - extracellular solute concentration higher that intracellular solute concentration, he water will diffuse our of the cell, and the cell may shrink and die. Hypotonic- extracellular solute concentration is lower than intracellular solute concentrations the water will diffuse in the the cell, and the cell may swell and burst.
41
Define endocytosis
The plasma membrane “traps” some extracellular material and brings it into the cell. (This is caused by cytoskeleton, receptor-mediate endocytosis)
42
What is the cytoskeleton known as
The internal scaffolding of the cell
43
Flagella is
Sperm
44
Plasma membrane is
Lipid bilayer-phospholipid bilaye
45
Desmosomes are like?
Velcro
46
Gap junctions are like?
Doors for greater communication
47
What does an open door mean in passive transport
An open door allows for free movement sometimes we just have to open the door.
48
What does active transport require
It requires ATP and to actively pull things across the lipid bilayer
49
What is an example of diffusion
An old fashioned when the sugar cube diffuses evenly across the drink
50
Diffusion is always in relation to what
Relation to solutes
51
During diffusion molecule will always do what
Molecules will move from a area of higher concentration to an area of lower concentration
52
Osmosis deals with what
Osmosis deals with solvents, and works through the movement of water will going from a low solute to a high solute
53
In diffusion directly through the lipid belayer how do things move
They simply pass in and out
54
In diffusion through protein Channels in the belayer how do things move
Water of ions will come through the ‘open door’ sometimes you will have to open the door
55
In facilitate transport how do things move
Insulin will come along the cell and knock on the door. It is shown that Glu 4 will then come change shape and open the door to let in insulin
56
Passive transport does not require what
Energy
57
Active transport requires what
Energy
58
In Ca++ pumps what happens
It is placed into the endoplasmic reticulum and then placed into the body
59
You have to exchange how many sodium for how many potassium
3 sodium for 2 potassium
60
Phagocytes bring in what
They bring in solutes and are “cell-eating”
61
Pinocytes bring in what
They bring in solvents and are “cell-drinking”
62
Define exocytosis
The process by which large molecules (proteins) can leave the cell even though they are too large to move out through the membrane
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