Review for Exam 2 Flashcards
1
Q
when did simple bacteria evolve?
A
4 billion years ago
chemotrophic - survived on chemicals
2
Q
when did photosynthetic cyanobacteria start to appear on earth?
A
2.5 billion years ago
autotrophic - made own food/released O2
3
Q
ribozyme
A
RNA with catalytic activity
4
Q
light microscope
A
- observe live specimens
- natural colors or with stains
5
Q
transmission electron microscope (TEM)
A
- used to study internal ultrastructures & cross sections of cells/structures
- electron beams aimed at thin section of a specimen
- has been stained with metal to absorb electrons (enhances contrast)
6
Q
scanning electron microscope (SEM)
A
- used to view the surface features & 3-D shape of ultrastructures
- specimen is coated with gold
- electron beams scan surface, which excites the secondary electrons on the sample surface
7
Q
cell fractionation
A
centrifugation is used to disrupt cells
- harvest tissues either fresh or been frozen (-700C / liquid N2)
- grind cells in buffer or N2. Keeps enzymes inactive
- homogenize cells in a buffer
- centrifuge a various speeds & durations to isolate components
8
Q
gel electrophoresis
A
- franctionates DNA, RNA, or protein molecules based on size
- negative charge of DNA & RNA make them migrate towards the (+) anode thru tiny pores in gel
- migrate depending on size & electric voltage of system
- larger ones move slowly; smaller ones move fast
- if voltage is increased, they move faster
9
Q
polyacrylamide gels
A
- used to fractionate proteins & DNA sequencing reactions
- in gel electrophoresis
10
Q
agarose gel electrophoresis
A
- used to fractionate DNA or RNA
11
Q
tight junctions
A
animal cell
2 cells are fused together
- prevents anything from passing
- epithelial cells in stomach
12
Q
gap junctions
A
animal cell
- connections between 2 cells thru connexons
- chemical signals or solutes can pass from one cell to another
- ex. heart muscle cells use to communicate
13
Q
desmosomes (aka anchoring junction)
A
animal cell
aka anchoring junction
- spots where cells are connected by keratin-like fibrous proteins
- not as tightly sealed at tight junctions (some space between 2 cells)
14
Q
cell junctions between plant cells
A
middle lamella
plasmodesmata
15
Q
what layers does something need to get through to get inside a plant cell?
A
middle lamella (between cells)
primary cell wall
secondary cell wall
plasma membrane
16
Q
what layers does something need to get through to get inside an animal cell?
A
plasma membrane
- proteins
- phospholipids
- glycolipids
- glycoproteins
- sterol
17
Q
what layers does something need to get through to get inside an plant cell?
A
middle lamella (between cells)
primary cell wall
secondary cell wall
plasma membrane
18
Q
Function of: phospholipids
A
structure and fluidity
19
Q
Function of: anchored proteins
A
structure
enzyme
20
Q
Function of: transmembrane proteins
A
structure
transport
receptor
enzyme
21
Q
Function of: oligosaccharides
A
AKA glycoprotein
cell to cell recognition
22
Q
Function of: sterol / cholesterol
A
fluidity
23
Q
Function of: peripheral proteins
A
structural
enzymatic
24
Q
types of cellular communication
A
- intracellular - e.g. between cytoplasm & other organelles
- intercellular
- gap junctions
- paracrine - close by cells (cells release something that targets local cells)
- endocrine - far away cells (travels thru bloodstream)stag
- synaptic - nerve cells - between organisms - uni- or multi-cellular
25
stages of cellular communication
1. signal reception
2. transduction
3. response
26
ligand
a molecule that specifically binds to another molecule, often a larger one
27
what happens during a cell signal pathway?
1st messenger signals a protein on the membrane (usually a G-protein coupled receptor)
This activates a specific protein (G-protein)
Which activates an enzyme (adenylyl cyclase)
Which catalyzes conversion of ATP to cAMP
-- cAMP acts as 2nd messenger
-- in turn, activates more proteins
Ultimately, causes a cellular response
28
Name small, polar groups
| How do they get through membrane?
1. H2O
2. Na+
facilitated diffusion
active transport
29
Name small, non-polar groups
| How do they get through membrane?
CO2
O2
CH4
simple diffusion
30
medium polar groups
| How do they get through membrane?
amino acid
glucose
sucrose
charged ions (Na+, Cl-)
facilitated diffusion
active transport
31
medium non-polar groups
| How do they get through membrane?
steroid
lipid soluble vitamins
simple diffusion
32
ion channels
transport proteins imbedded in the cell membrane that facilitate the transport of charged ions & molecules across the membrane
33
uniport
single solute
one direction
e.g. H+ pump
34
symport
two solutes
moving in one direction (same)
e.g. sucrose/H+ pump
35
antiport
two solutes
moving in opposite directions
e.g. Na+/K+ pump
36
large polar groups
| How do they get through membrane?
protein
DNA
RNA
exocytosis - leaving cell
endocytosis - bring into cell
37
large non-polar groups
| How do they get through the membrane?
fat globules
LDL
HDL cholesterol
exocytosis
endocytosis
38
exocytosis
the organelle that contains something that needs to leave the cell fuses with the plasma membrane and opens outside to secrete the material
39
endocytosis
phagocytosis - macrophage engulfing bacteria ID for destruction
pinocytosis - taking in liquids
receptor mediated endocytosis - specific receptor proteins recognize large molecules (cholesterol), change conformation & engulf LDL for cell processing
40
Smooth ER
No ribosomes attached
Synthesizes lipids
Participates in carbohydrate metabolism
Detoxifies unwanted chemicals including drugs
Stores Ca2+ necessary for muscle contraction
41
Rough ER
Ribosomes attached for membrane protein synthesis
| - synthesizes membrane-bound proteins for secretion
42
Golgi apparatus
Central receiving & dispatching center (proteins made in ER are sorted & packaged into vesicles & shipped to target sites
43
Lysosomes
Membrane bags with hydrolytic enzymes (that come from Golgi or ER)
Acidic pH 5.0
Digest food
Excretes digested material into if wanted or outside cell if not
44
Peroxisomes
Both plant and animal
Responsible for lipid degradation
Detoxification of active oxygen species
Contain enzymes - peroxidase & catalase
45
Glyoxysomes
Plants only
Specialized Peroxisomes
Facilitate breakdown of storage lipids in germinating seeds
46
Large central vacuole:
Found only in plants
| Stores organic compounds, waste products, lytic enzymes, pigments and water
47
Contractile vacuole
in fresh water protists
| help remove excess water from cell
48
energy organelles
- mitochodria - impt for utilization of carbohydrates
| - chloroplasts - imp for generation of carbohydrates
49
Similarities between mitochondrion & chloroplasts
- double membrane structure
- have their own DNA & proteins
- replicate autonomously
- make ATP
- import some proteins from cytoplasm
- used for evolutionary studies
50
Differences between mitochondrion & chloroplasts
mitochondrion - found in all higher eukaryotes
- perform respiration
chloroplasts - found in plants only
- perform photosynthesis & amino acid biosynthesis
51
Endosymbiotic theory
- proposed to explain how eukaryotic cells acquired chloroplasts & mitochondria
- theory is that early primitive eukaryotes engulfed bacteria & other prokaryotes that had energy generating functions
52
parts of mitochondrion & chloroplasts that correspond
1. inner membrane - same
2. cristae (m) -- thylakoid (c)
3. outer membrane - same
4. matrix (m) -- stroma (c)
5. inner membrane - same
53
parts that are unique to plant cells
1. central vacuoles
2. cell wall
3. chloroplasts
4. plasmodesmata
54
parts that are unique to animal cells
1. lysosomes
2. centrosomes (w. centrioles)
3. flagella
55
plastids
plant organelles
make & store needed compounds
chloroplast is one
56
what are the 3 major types of cytoskeleton elements?
1. microtubules
2. microfilament
3. intermediate filaments
57
microtubules
hollow tubes
made of alpha & beta tubulin (monomer)
Help in:
1. cell motility (flagella, cilia)
2. cell shape
3. chromosome movement
4. serve as tracks for movement of organelles
58
mircofilaments
```
small filamentous
actin filaments (in all eukaryotes); myosin only in animal cells
Help in:
1. amoeboidal movement
2. muscle contraction
3. cytoplasmic streaming
4. cleavage furrow during cell division
```
59
intermediate filaments
```
hollow tubes made of keratin-like
almost all eukaryotic cells
Help in:
1. structural support
2. tensile strength
3. cell shape
4. anchoring nucleus & other cell organelles
5. formation of nuclear lamina
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