Exam #2 vocab Chapter 3 Flashcards
1
Q
Hooke
A
1600s
-first to observe cells thru microscope-looking at plants
2
Q
Schleiden & Schwann
A
1830s
-came up with idea that all living things are made up of cells
3
Q
Virchow
A
1850s
- cells only arise from other cells
ex. mitosis
4
Q
plasma membrane
A
separates the intracellular fluid from the extracellular fluid
5
Q
cytoplasm
A
cellular material between the plasma membrane and the nucleus. Site where most cellular activities are accomplished. Made of 3 major elements:
- cytosol
- organelles
- inclusions
6
Q
nucleus
A
control center of the cells, contains genetic info
7
Q
diffusion
A
- passive process
- where molecules or ions move from an area of higher concentration to area of lower concentration
- they move “down” the concentration gradient
8
Q
membrane potential
A
voltage across the membrane - its electrical potential energy from the separation pf oppositely charged particles.
-typically ranges from -50 to -100 mV (millivolts)
9
Q
gene
A
segments of DNA that code for one polypeptide chain (protein)
10
Q
exon
A
amino acids specifying sequences
11
Q
intron
A
non-coding sequences
-junk DNA
12
Q
cell differentiation
A
development of specific features in the cells
- allows embryo stem cells to develop into all cell types.
- differentiation is probably dependent on different chemical signals that channel them into specific developmental pathways.
13
Q
apoptosis
A
programmed cell death
14
Q
codon
A
3 base mRNA for each three sequence DNA sequence
15
Q
anti-codon
A
a 3 base sequence complimentary to the mRNA coding fro the amno acid carried by tRNA
16
Q
integral membrane protein
A
firmly inserted into the bilayer, many go all the way through
-used for enzymes, used for transport (either as channels or carriers) or as receptors for hormones
17
Q
peripheral membrane protein
A
loosely attached to integral protein, could be in intra or etxra positions
18
Q
tight junction
A
protein molecules are fused together to form an impermeable junction, connection between cells
ex. cells lining digestive tract
19
Q
desmosomes
A
- binding body
- anchoring junctions, act to distribute tension to reduce risk of tearing
ex. skin cells need to stretch, heart beats-changes shape
20
Q
gap junction
A
cell-cell communication -spaces for small molecules to go between cells
ex. ions, simple sugars
- in heart
21
Q
cell adhesion molecules
A
involved in embryonic development, wound repair, and immunity
-type of glycocalyx molecule
22
Q
contact signaling
A
cells actually physically touch one another, they recognize each other
-important- in development and driving immunity
23
Q
chemical signaling
A
- ligands -signalling chemicals that bind to specific membrane receptors
- ex. neurotransmitters, hormones
24
Q
glycocalyx
A
-glyco-proteins with sugar groups and occur in the cells surface, used in cell, cell recognition
25
mitochondria
power plants of the cell
- job is to harvest chemical energy in food, use this energy to create ATP
- mito. is usually clustered where the action is.
- busy cells (kidney & liver) have more mitochondria
- 2 membranes: smooth outermembrane and a folded inner membrane
26
ribosomes
made of proteins and RNAs
| -site of protein synthesis
27
rough endoplasmic reticulum
contains ribosomes that manufacture proteins secreted from cells.
- makes components for membranes
28
smooth endoplasmic reticulum
enzymes catalyzing many reactions- NO role in protein synthesis:
1- lipid metabolism, cholesterol synthesis
2-synthesis of steroid-based hormones(sex horm.
)
3- absorb, synthesize & transport fats
4- detox certain drugs, pesticides and carcinogens
5- breakdown the stored glycogen to form free glucose (liver cells)
29
Golgi apparatus
- postal distribution center-traffic director for cellular proteins
- consists of stacked & flattened membraneous sacs, shaped like hollow dinner plates
- GA receives transport vesicles from thh Rough ER, modifies them(ex.adding phosphate), sorts them out the other side
30
lysosomes
contain digestive enzymes, its their job to break things down:
a) digesting particles, taken in by endocytosis(bacteria, toxins)
b) breakdown organelles that are worn out
c) perform metabolic functions(ex. glycogen breakdown/release)
d) breakdown nonuseful tissues(ex. uterine lining-period)
e) beak down bone to release calcium ions into the blood
31
cytoskeleton-microtubules
large hollow tubes, determine cell shape and distribution of organelles
-motor proteins-powered by ATP, transport organelles along microtubules
32
cytoskeleton-microfilaments
thin, made of actin, strengthen the cell surface, involved in cellular movement
ex. in muscle cell contraction
33
cytoskeleton-intermediate fibers
tough, insoluble proteins with high tensile strength
| -attach to desmosomes and act as guide wires to resist pulling forces exerted on the cell
34
cellular extension- flagella
long projections formed by centrioles; propel entire cell.
| Ex.cell
35
cellular extension-cilia
whiplike motile cellular extensions occurring in great numbers on some cell surfaces.
Ex. respiratory tract-pseudostrat ciliated columnar
36
cellular extension-microvilli
tiny finger-like extensions of the plasma membrane projecting from a free cell surface. Ex. intestine, kidney - increased surface area for absorption
37
which mature body cell not have a nucleus
red blood cell- needs more room to carry O2
38
function of nuclear envelope
- double membrane barrier separated by a fluid-filled space
1. the outer surface is studded with ribosomes and the inner membrane is lined by nuclear lamina, which help maintain the shape of the nucleus
2. nuclear pores(holes that form protein transport channels)
3. encloses a jell-like fluid called the nucleoplasm(liquid part of nucleus)
39
nucleoli
found in nucleus, not bound by membranes
| - these are the sites where ribosomal subunits are assembled
40
chromatin
- made up of 30% DNA, %60 histone proteins and ~ 10% RNA chains
- nucleosomes-fund. units of chromatin, 8 histone P. connected by DNA
- histone-pack DNA molecules into compact form, gene regulation
- chromatin is usually not visible in the cell, but when it condenses to form chromosomes before cell division it is dense enough to be seen
41
3 tyoes of RNA
- Ribosomal RNA-rRNA
- Messenger RNA-mRNA
- Transfer RNA-tRNA
42
ribosomal RNA
- constituent of ribosome
| - exists within ribosomes of cytoplasm and assists in protein synthesis
43
transfer RNA
short chain RNA molecules that transfer amino acids to the ribosome
44
messenger RNA
long nucleotide strands that reflect the exact nucleotide sequences of the genetically active DNA and carry the message of the latter.
45
cytokinesis
division of cytoplasm, formed when cleavage furrow pinches apart
46
active vs. passive transport
substances can cross the plasma membrane either passively(always occurs via diffusion) without any energy input, or actively, with help of ATP.
47
diffusion
where molecules or ions move from an area of higher concentration to an area of lower concentration - down their concentration gradient
48
simple diffusion
nonpolar and lipid soluble substances diffuse directly through lipid layer
49
facilitated diffusion
glucose, amino acids & ions- go straight across or with help of carrier proteins -passive trans
50
osmosis
diffusion of a solvent, often water, through a selectively permeable membrane, something liquidy, particles can go through
- water passes through aquaporins
- water is moving- moves from areas of higher water lower solute to areas of lower water & higher solute, until equilibrium occurs
51
tonicity
ability of cell to change its shape by altering internal water volume
52
isotonic
concentration of particles is the same inside & out
| -no net movement
53
hypertonic
more solutes outside, water will leave the cell-cells shrivels- crenates
54
hypotonic
more solutes on the inside than outside - water will move into the cell; cell will eventually burst-lyse
55
primary active transport
-requires carrier proteins that combine with the substance to be transported, but requires energy because it is pumping molecules against their concentration gradient.
Ex. CA2+, Na+,
56
secondary active transport
when an ion is actively pumped across a membrane, it will leak back through with help of a carrier protein, this can drag or Cotransport other things with it
57
Symport
both substances move in same direction
| Ex. sugars, amino acids, ions
58
antiport
substances move in opposite directions - "wave to eachother"
| ex. regulation pf pH by driving out H+ ions
59
vesicular transport
- energized by ATP (or GTP) -active transport
- fluid-containing large particle, macromolecules are transported across cellular membranes inside membraneous sacs called "vesicles"
- processes that eject substances, from cell interior into extracellular fluid are called "exocytosis"
60
types of vesicular transport
exocytosis, endocytosis, transcytosis, substance trafficking
61
exocytosis
transport out of cell
| ex. secretion of neurotransmitters, hormones, mucus, ejection of cell wastes
62
endocytosis
transport into the cell
| ex. WBC, macrophages, dissolved solutes, some hormones, cholesterol, iron and most macromolecules
63
transcytosis
movement into, across, then out of cell
64
substance(vesicular) trafficking
transport from one area of the cell to another area
65
types of endocytosis
- phagocytosis
- pinocytosis
- receptor-mediated endocytosis/transcytosis
66
phagocytosis
cellular eating
| e. WBC engulfs a bacteria
67
Pinocytosis
cellular drinking, allows sampling of extracellular fluid
| ex. cells in intestine use this to absorb nutrients
68
Receptor-mediated endocytosis and transcytosis
very selective receptors in the membrane bind only to certain substances
ex. hormones, enzymes but also flu, diphtheria, and Cholera(trick cells into taking them in)
69
helicase
- in DNA replication
| - helicase enzyme unwinds the DNA double helix to form a replication fork
70
nucleotide
each nucleotide strand serves as a template to build new strand
71
DNA polymerase
after RNA primers initiate DNA synthesis:
the enzyme polymerase assembles in short segments free base pairs to their matching complimentary bases open on the DNA replication fork.
72
DNA ligase
DNA ligase then splices together the short segments assembled by DNA polymerase
-glues segments
73
RNA polymerase, mRNA & nucleotides, terminal signal
-used in transcription(protein synthesis)
-RNA polymerase pulls apart the strands of DNA double helix so that transcription can begin at promoter(DNA sequence start point).
- RNA polymerase creates a new mRNA strand by adding a free RNA nucleotides to the DNA strand as it unwinds the double helix- only a little DNA unwound at a time
-the polymerase reaches a termination signal, transcription finished and new mRNA strand drops off
-finally, mRNA has to edited before it can move on
Spliceosomes come in and remove introns(junk DNA), then splice together remaining exons
74
codons
for each three sequence DNA triplet, there are three base mRNA called codon
75
Ribosome role in translation
- mRNA hooks up with ribosome when it leaves the nucleus
| - ribosome also contains rRNA
76
translation
language of nucleic acids(base pairs), translated into language of proteins
