Chapter 3 - Cells Flashcards
1
Q
Main cellular components:
A
Plasma membrane
Cytoplasm
Nucleus
2
Q
Plasma membrane is:
A
A flexible outer covering of a cell, separating the inside and outside environment of a cell which plays a key role in communicating among cells and acts as a barrier
3
Q
The plasma membrane consists mostly of:
A
Lipids and proteins
4
Q
The lipid layer is made up of
A
3 types of lipid molecules:
Phospholipids
Cholesterol
Glycolipids
5
Q
2 types of proteins in the plasma membrane:
A
Integral proteins - extend into or through the lipid bilayer
Peripheral proteins - loosly attached to the external or internal surface of the membrane
6
Q
Glycoproteins are
A
Peripherial proteins
7
Q
The plasma membrane has ________ permeability
A
Selective
8
Q
What is the plasma membrane permeable and not permeable to?
A
Permeable to water, fatty acids, fat soluable vitamins, steroid, oxygen, and Carbon dioxide
Not permeable to ions, glucose, and AAs
9
Q
Some integral proteins from iron channels through which …
A
Potassium ions can move into and out of the cell
10
Q
Carriers (transporters) do what
A
Change shape as they move a substance from one side of the membrane to the other
11
Q
What is unable to pass through the plasma membrane within the vesicles?
A
Proteins
12
Q
integral proteins are called what?
What do they recognize?
A
Called receptors
Recognize and bind a specific molecule
13
Q
Enzymes do what
A
Speed up specific chemical rxns
14
Q
What are cell identity markers and what do they do?
A
Membrane glycoproteins and glycolipids
They recognize and respond to potentially dangerous foreign cells
15
Q
Intracellular fluid (ICF)
A
The cytosol o fa cell, inside the body cell, 2/3rd of body fluid
16
Q
Extracellular fluid (ECF)
A
Outside the body cell
17
Q
Interstitial fluid
A
In themicroscopic spaces between the cell of tissues
18
Q
Plasma
A
Extracellular fluid in blood vessels
19
Q
Lymph
A
Extracellular fluid in the lymphatic vessels
20
Q
Cerebrospinal fluid (CSF)
A
Extracellular within and around the brain and spinal cord
21
Q
Materials disolved in body fluids is called
A
A solute
22
Q
Solvent
A
The fluid in which it is dissolved (water)
23
Q
Concentration
A
The amt of solute in a soln
24
Q
Concentration gradient
A
The difference in concentration between two different areas, the intracellular and extracellular fluid
25
Substances move across cellular membranes by two processes:
Passive process
| Active process
26
Passive process
A substance moves down its concentration gradient through the membrane using only kinetic energy
Ex: diffusion and osmosis
27
Active process:
Cellular energy is in the form of ATP is used to push the substance through the membrane
28
Two types of diffusion:
Simple and facilitated
29
Simple diffusion:
Substances diffuse across a membrane through the lipid bilayer
Ex: exchange of oxygen and carbon dioxide between the blood and body cells, between blood and air within lungs during breathing, transport method for absorption of lipid, and release of wastes from body cells
30
Facilitated diffusion is when
Some substances cannot move through simple diffusion and involves ion channels when ions move down their concentration gradients across the lipid bilayer
Ion Channels:
- potassium ions
- chloride ions
- sodium ions
- calcium ions
31
Substances that need carriers:
1) glucose
2) fructose
3) galactose
4) some vitamins
32
Osmosis is
A passive process in which water moves from an area of higher water to an area of lower water concentration
33
Osmotic pressure is when
A soln containing solute particles that cannot pass through a membrane and that exerts pressure on the membrane
34
Isotonic soln
Cells maintain their nml shape and volume and the conc of solutes are the same on both sides
35
Hypotonic soln
Lower conc of solutes
36
Hypertonic soln
Higher conc of solutes
37
Hemolysis
Rupture of the red blood cells
38
Crenation
Shrinkage of red blood cells
39
Energy derived from splitting ATP changes the shape of a carrier protein and now it is called a
Pump
40
A pump moves a substance when?
It needs to go against its concentration gradient
41
All cells have thousands of sodium potassium pumps in their plasma membranes which is what?
The most important active transport that expels sodium ions from cells and brings in potassium ions.
42
A vesicle is
A small rounded sac that transports substances from one structure to another, takes in extracellular fluid, and releases substances into the extracellular fluid
43
Two main types of transport in vesicles are called:
Endocytosis - move into a cell
- phagocytosis and pinocytosis
Exocytosis - move out of a cell
- sensory cells and nerve cells
44
Phagocytosis
Cell eating
Pseudopods reach out and grab the large molecule, then the pods fuse to form a phagosome and that enters into the cell.
45
Residula body
Undigested material remain indefinitely in a vesicle
46
Phagocytosis occurs only in
Phagocytes
White blood cells and macrophages
Protects the body from dz
47
Pinocytosis
Cell drinking
Where cells take up tiny droplets of extracellular fluid
48
Exocytosis results in
Secretion
Secretory cells
Nerve cells - nerotransmitters
49
Cytoplasm consists of
All the cellular contents, both cytosol and organelles
50
Cytosol is the site of
Many chemical rxns
51
The liquid portion of the cytoplasm accounts for what % of the total cell volume?
55%
52
Cytoskeleton
A network of three different protein filaments extending through the cytosol
1) microfilaments
2) intermediate filaments
3) microtubules
53
Microfilaments are
The thinnest elements of the cytoskeleton
They contribute to the strength and shape of the cell
Movement, anchor, muscle contractions for locomotion and divisions
54
Microvilli are
Fingerlike projections that increase the surface area of the cell
55
Intermediate filaments are
Thicker than microfilaments
Thinner than microtubules
Found in parts of the cells subject to tension (stretching)
Helps hold organelles such as nucleus in place
56
Microtubules are
The largest of the cytoskeletal components
Long, hollow tubes
Help determine shape/function, migration of chromosomes, movements of cilia and flagella
57
Organelles are
Specialized structures inside cells that has its own unique set of enzymes that have characteristic shapes and specific functions
58
Centrosome is located where
Near the nucleus
Has its own pair of centrioles and pericentriolar material
59
Centrioles are
Two cylindrical structures with:
9 clusters of 3 microtubules (triplet) arranged in a circlular pattern
Surrounding centrioles are ring shaped proteins called tubulins
60
Role of a tubulin
Organizing center for growth of mitotic spindle
Plays a critical role in Cell division
61
Cilia and flagella are
The motile projections of the cell surface formed from microtubules
Cilia are numerous and short. They propell fluids across the surfaces of cells (respiratory tract)
Flagella are much longer and usually move the entire cell (sperm cell)
62
Ribosomes are
Function: protein synthesis
High content of RNA
Contain ribosomal proteins
Large and small subunits
Attached to outer surface of the nuclear membrane and endoplasmic reticulum
Located w/in the mitochondria
63
Endoplasmic reticulum (ER) is a...
Network of folded membranes in the form of flattened sacs or tubules that extend throughout the cytoplasm
Rough ER
Smooth ER
64
Rough ER
Extends from the nuclear envelope and appears rough because its studded with ribosomes
Function: synthesize secretory proteins, membrane molecules, glycoproteins, and phospholipids
65
Smooth ER:
Extends from the Rough ER to form a network of membraneous tubules (lacks ribosomes - smooth)
66
What are synthesized in the smooth ER
Fatty acids and steroids
67
Enzymes of the smooth ER in liver cells do what
Release glucose into blood stream and inactivate/detoxify drugs
68
Enzymes of the smooth ER in muscle cells do what
Release calcium ions for muscle contraction w/ the help of sarcoplasmic reticulum
69
Golgi complex are
More extensive in cells that secrete proteins
First step in the transport pathway
Consists of 3-20 cisterns
Function: modify and package proteins
70
What is it called when proteins are discharged from the cell
Exocytosis
71
Lysosomes
Membrane-enclosed vesicles that contain as many as 60 different digestive enzymes
Function: recycle wornout organelles (autophagy)
Destroy entire cells (autolysis)
72
Lysosomal membrane contains
Carrier proteins that allow the final products of digestion
73
Peroxisomes are
Smaller units abundant in the liver where detoxification of harmful substances takes place
Contain catalase that decompose H2O2
Function: Protects other parts of the cell from toxic effects
74
Proteasomes are
Tiny barrel shaped structures found in both the cytosol and nucleus containing enzymes.
Function: continuous destruction of unneeded/damaged, or faulty proteins
75
Mitochondria are
The powerhouse of the cell
Site of ATP production
Liver and kidneys
Outer membrane smooth
Inner membrane series of folds called mitochondrial crista
Function: degrades damaged proteins by cutting them into small peptides
76
What part of the mitochondria contains enzymes?
Mitochondrial matrix
77
Nucleus is
The largest organelle of the cell
Control center of the cell
Mature RBC have no nucleus
Skeletal muscle cells have a nucleus
78
Nuclear envelope is
A dbl membrane that separates the nucleus from the cytoplasm
Continuous with the rough ER
79
Nuclear pores are
Many openings that pierce the nuclear envelope
Control mmt of substance between the nucleus and cytoplasm
80
Nucleoli are
One or more spherical bodies inside the nucleus
Muscle and liver cells have prominent nucleoli
81
Genes are
Most of the hereditary units of a cell found within the nucleus
Control cellular structure and direct cellular activities
82
Nuclear genes are arranged along
Chromosomes
83
Human body cells (somatic) have how many chromosomes?
46
23 from each parent
84
In a cell that is not dividing the 46 chromosomes appear as a diffuse granular mass which is called ...
Chromatin
85
The total genetic info carried in a cell or organism is called its
Genome
86
Whats the DNAs job in genes
Instruction for making proteins
87
What must happen to DNA to synthesize a protein?
It must be transcribed (copied) to form RNA
88
What happens to cells when they become damaged/diseased/worn out
Replaced by cell division
2 types:
Reproductive and somatic
89
Somatic cell division occurs where
In all body cells except the gamets
90
In what sequences does a cell divide in somatic cell division?
Replication (duplication) of the DNA that make up genes and chromosomes so that the same genetic material can be passed on to newly formed cells
91
Somatic cell division replaces what?
Dead or injured cells and adds new ones for tissue growth
Ex: skin cells are continually replaced by somatic cell divisions
92
Reproductive cell division or meiosis is
The process that produces gametes (sperm and oocytes) that the cell needs to form the next generation of sexually reproducing organisms
93
Cell cycle is the
Sequence of changes that a cell undergoes from the time it forms until it duplicates its contents and divides into two cells
94
In somatic cells, the cell cycle consists of two major periods, what are they?
Interphase - when a cell is not dividing
| Mitosis - when a cell is dividing
95
Interphase is the phase in which a cell does what
Copies its DNA in preparation for mitosis
96
Mitosis consists of what two things
Karyokinesis - division of the nucleus
Cytokinesis - division of the cytoplasm into two cells
97
what does chromatin do
Condenses into chromosomes
98
Nuclear division is the
Replication and distribution of 2 sets of chromosomes into separate and equal nuclei
99
Mitosis consists of what 4 phases
Prophase, metaphase, anaphase, telophase
Prop Met Ana over the Telophone
100
What happens during early prophase
The chromatin fibers condense and shorten into chromosomes
Each chromosomes consist of double stranded chromatids
A constricted region of the chromosome is called the centromere - holds the chromatid pair together
101
Late prophase
The pericentriolar material of 2 centrosomes starts to form the mitotic spindle
Microtubles lengthen pushing centrosomes to opposite poles (ends) of the cell
Spindle extends from pole to pole and nucleolus and nuclear envelope break down
102
Metaphase
The centromeres of the chromatid pair are aligned along the microtubules of the mitotic spindle at the center of the mitotic spindle
Midpoint is called the metaphase plate
103
Anaphase
Centromeres split separating the two chromatids and move them to opposite ends of the cell
Separated chromatids are called chromosomes
104
Telophase begins when
After chromosomal movement stops
105
Cytokinesis is
The division of a cells cytoplasm and organelles
Begins late anaphase w/ the formation of a cleavage furrow in the plasma membrane
Microfilaments in the cleavage furrow pull the plasma membrane inward constricting the center of the cell
106
Cellular diversity means that the human body is comprised of trillions of cells that vary in size and shape and are measured how
In units called micrometers
1 micrometer = 1 one-millionth of a meter
107
The largest cell is called
A single oocyte - barely visible to the unaided eye
108
Shapes of cells are related to their
Function
109
Sperm cell shape
Long tail (flagellum) uses it for locomotion
110
RBC shape
Disc shape w/ lg surface area that enhances its ability to pass oxygen to other cells
111
Smooth muscle cells shape
Long spindle shape shortens as it contracts and changes shape to allow the passage for blood flowing through vessels
112
Microvilli shape
Epithelial cells that line the small intestine provide a lg surface area that speeds up the absorption of digested food
113
Nerve cells shape
Long extensions that permit them to conduct nerve impulses over great distances
114
What is aging?
A nml process accompanied by a progressive alteration of the body’s homeostatic adaptive responses
115
Aging produces what
Observable changes in structure and function and increases vulnerability to environmental stress and dz
116
Geriatrics is what
The specialized branch of medicine that deals with the medical problems of elderly persons
117
Gerontology is the
Scientific study of the process and problems associated with aging
118
What are specific DNA sequences found only at the tips of chromosomes that has to do with aging
Telomeres
They shorten w/ each cell division over time
Eventually they are completely gone which leads to aging and death of cells
119
Glucose
Most abundant sugar in the body
| Plays a role in the aging process
120
Autoimmune response might be caused by
The changes in certain plasma membrane of glycoproteins and glycolipids that cause antibodies to attach the cell for destruction
Known signs of aging
Wrinkled skin, stiff jnts, hardened arteries
