ch.3 Flashcards
(90 cards)
1
Q
4 functions of the plasma membrane
A
- physical isolation
- regulation of exchange
- sensitivity to environment
- structural support
2
Q
hydrophilic head of phospholipid bilayer
A
face outward to the watery environments of the extracellular fluid and the intracellular fluid (cytosol)
3
Q
hydrophobic tail of phospholipid bilayer
A
form the inside core of the membrane and act as a barrier to ions and water-soluble compounds
4
Q
3 components of the glycocalyx
A
- proteoglycans
- glycoproteins
- glycolipids
5
Q
4 functions of the glycocalyx
A
- lubrication & protection
- anchoring specialized cells
- specificity in binding
- recognition
6
Q
receptor proteins
A
bind and respond to ligands
7
Q
carrier proteins
A
bind and transport specific solutes
8
Q
channels
A
integral proteins that permit water and small solutes to flow
9
Q
gated channels
A
open and close to regulate passage of substances
10
Q
cytoplasm
A
contains materials between the plasma membrane and the nucleus
11
Q
cytosol
A
intracellular fluid where organelles and inclusions are held
12
Q
organelles
A
internal structures with specific functions
13
Q
inclusions
A
insoluble material inside cells
14
Q
cytoskeleton
A
provides shape, strength and flexibility
15
Q
microfilaments
A
- composed of actin
- provide mechanical strength
16
Q
3 contents of the cytoskeleton
A
- microfilaments
- intermediate filaments
- microtubules
17
Q
intermediate filaments
A
strengthen the cell and maintain its shape
18
Q
microtubules
A
- hollow tubes of tubulin
- form the spindle apparatus during cell division
- form the centrioles and cilia
19
Q
microvilli
A
finger-shaped projections that increase surface area for absorption
20
Q
centrioles
A
- form spindle apparatus during cell division
- located in the centrosome
21
Q
centrosome
A
microtubule-organizing center
22
Q
cilia
A
extensions of the plasma membrane containing microtubules
23
Q
ribosomes
A
synthesize proteins
24
Q
proteasomes
A
contain proteases which break down proteins
25
rough endoplasmic reticulum
has ribosomes that modifies and packages proteins
26
smooth endoplasmic reticulum
synthesizes lipids and carbohydrates
27
golgi apparatus
stores and packages secretory products
28
lysosomes
vesicles containing digestive enzymes that remove damaged organelles or pathogens
29
peroxisomes
vesicles containing enzymes that break down toxic compounds like fatty acids
30
mitochondria
produce 95% of the ATP used by cells
31
3 functions of the nucleus
- controls cellular metabolism
- stores and processes genetic info
- controls protein synthesis
32
genetic code
- sequence of bases (A, T, C, G)
- DNA instructions of how to build proteins
- 3 bases=1 amino acid
33
transcription
synthesis of RNA from a DNA template
34
messenger RNA (mRNA)
carries the transcribed info for the sequence of amino acids in a protein from the nucleus to the cytoplasm
35
translation
synthesis of a polypeptide based on the instructions in mRNA
36
transfer RNA (tRNA)
delivers amino acids during translation
37
mutation
permanent changes in a cell's DNA that affect the nucleotide sequence and can result in changes in proteins
38
passive process & 3 types
- no energy required
- diffusion
- osmosis
- facilitated difusion
39
active process & 3 types
- requires energy in the form of ATP
- active transport
- endocytosis
- exocytosis
40
simple diffusion
allows lipid-soluble compounds to cross the lipid portion of the membrane
41
channel-mediated diffusion
allows water-soluble compounds to pass through a membrane channel
42
osmosis
- net diffusion of water across a membrane that is permeable to water
- water diffuse towards the solution with higher solute
43
osmotic pressure
the force with which pure water moves into a solution
44
hydrostatic pressure
the pressure that opposes the osmotic pressure
45
isotonic solution
equal concentration of solute as the cell
46
hypotonic solution
- has lower solute concentration than the cell
- causes the cell to swell and may rupture (hemolysis)
47
hypertonic solution
- has higher solute concentration than the cell
- causes the cell to shrink (crenation)
48
carrier-mediated transport
transport across specialized integral membrane proteins
49
symport (cotransport)
two substances move in the same direction at the same time
50
antiport (countertransport)
two substances move in opposite directions
51
types of carrier-mediated transport
- facilitated diffusion
- active transport
- primary active transport
- secondary active transport
52
facilitated diffusion
- diffusion through specialized carrier proteins
- passive
- for large molecules or insoluble in lipid
- carrier protein changes shape
53
active transport
uses energy (ATP) to move substrates against concentration gradient
54
primary active transport
pumps solutes against concentration gradient using ATP
55
sodium-potassium pump
- type of primary active transport
- pumps 3 Na ions out for every 2 K ions in (more sodium outside, more potassium inside)
56
secondary active transport
- uses established gradient from primary to move solutes
- ex. Na gradient drives glucose into cells
57
endocytosis
imports materials packages into vesicles
58
vesicular transport
materials move in or out of cell in vesicles
59
3 types of endocytosis
- receptor-mediated
- pinocytosis
- phagocytosis
60
receptor-mediated endocytosis
receptors (glycoproteins) bind the target molecules (ligands)
61
pinocytosis
- bring fluids and small molecules into cell
- "cell drinking"
62
phagocytosis
- phagosomes bring particles into cell
- "cell eating"
63
exocytosis
exports intracellular materials
64
membrane potential
- results from unequal distribution of positive and negative charges across the membrane
- indicates that the inside is more negative than outside
65
cell death
apoptosis
66
cell life cycle
- interphase
- prophase
- metaphase
- anaphase
- telophase
- cytokinesis
67
interphase
- the period between 2 cell divisions
- G1: duplication of organelles
- S: DNA replication, synthesis of histones
- G2: protein synthesis
68
M phase
mitosis and cytokinesis
69
mitosis
duplication of chromosomes and separation into 2 sets
70
cytokinesis
- division of cytoplasm
- produces 2 daughter cells
71
early prophase
- 2 pairs of centrioles
- astral rays and spindle fibers
- chromatin condenses & chromosomes become visible
72
late prophase
chromosome with 2 chromatids
73
metaphase
chromatids align at metaphase plate
74
anaphase
2 daughter chromosomes are pulled in opposite directions along the spindle apparatus
75
telophase
- nuclear membranes re-form
- chromosomes uncoil
- cleavage furrow
76
mitotic rate
- rate of cell division
- slower rate=longer life
- muscle and nervous cells rarely divide
- skin and GI cells are replenished
77
how can cell division be stimulated
- internal factors (M-phase promoting factor, MPF)
- extracellular chemical factors (growth factors)
78
how can cell division be inhibited
- repressor genes
- short telomeres (DNA segments that shorten throughout cell divisions)
79
benign tumor
remains within the tissue where it originated
80
tumor
a madd produced by abnormal cell growth and division
81
malignant tumor
aggressive tumor that spreads into tissues
82
primary and secondary tumor
- primary: tumor of origin
- secondary : spread of malignant cells from primary (metastasis)
83
cancer
caused by mutations in genes that cause cell growth, differentiation, or division
84
mutagens
agents that cause mutations
85
carcinogens
cancer-causing agents
86
cellular differentiation
turning off of genes which allows for the formation of different cell types
87
codons
determines the sequence of amino acids
88
anticodons
a sequence of nucleotides in tRNA that matches with a codon from mRNA
89
introns
noncoding sections of RNA transcript
90
exons
sections of DNA that code for proteins
