Exam 1(post ME 1) Flashcards
(72 cards)
1
Q
Why are prokaryotic cells typically smaller than eukaryotic cells?
A
Prokaryotic cells move molecules through diffusion which is limited by inner and outer environment concentrations reaching equilibrium
2
Q
Nuclear membrane
A
Inner and outer layers, made of lipid bilayer, outer later is connected to ER
3
Q
Vesicles
A
Move along microtubule tracts from ER to golgi
4
Q
Transcription location
A
nucleus
5
Q
Function of smooth ER
A
lipid synthesis
6
Q
ER lumen
A
space in ER
7
Q
Where does translation occur?
A
cytoplasm
8
Q
Characteristic of protein that need to pass through membranes
A
nonpolar
9
Q
soluble proteins
A
synthesized in cytoplasm
10
Q
Difference between membrane embedded protein synthesis and secreted protein synthesis
A
Embedded proteins have 2 signal sequences where transport stops
11
Q
cis vs trans golgi
A
Cis is the receiving side and trans in the shipping side
12
Q
How is the cell membrane built/repaired?
A
Vesicles carry phospholipids, lipids and protrin to make it bigger and take damaged phospholipids away
13
Q
Which cells have mitchondria?
A
all eukaryotes
14
Q
semiautonomous organelles
A
- mitochondria, chloroplasts, plastids
- reproduce/divide themselves
- depend on cell for some proteins
- could not survive on their own
- originated from endsymbiosis
15
Q
Where did mitochondria originate from?
A
Oxygen using, nonphotosynthetic prokaryotes
16
Q
Where did chloroplasts come from?
A
Photosynthetic prokaryotes
17
Q
Structure of mitochondria
A
- inner and outer membrane: inner membrane folds to increase surface area to make more ATP
- inter membrane space between inner and outer membrane
- Matrix: innermost, soluble portion of mitochondria, analogous to cytosol
- ribosomes
18
Q
Chloroplast structure
A
- 3 membranes: inner, outer, and thylakoid membrane
- Thylakoids are stacked, green and connected
- Inter-membrane space between inner and outer membrane
- Stroma: inner, soluble portion of chloroplast
- ribosomes
19
Q
Characteristics of multicellularity
A
- Organisms consist of more than one cell
- Cells adhere to and recognize one another
- Cell specialize and tissues form
20
Q
Do all plants and animals have tissues?
A
All animals except sponges, and all plants have a certain type
21
Q
Cytoskeleton
A
- Internal structure of the cell
- dynamic
- made of microtubules and filaments
- all cells have a cytoskeleton, it is more complex in eukaryotes
22
Q
Microtubules
A
- part of cytoskeleton
- Hollow tubes made of tubulin and dimers
- largest cytoskeleton component
- cell shape, motility, chromosome movement in division, organelle movement
- control flagellum
23
Q
Microfilaments
A
- Two intertwined strands of actin filaments
- aka actin filaments
- smallest part of cytoskeleton
- cell shape, muscle contraction, cell motility, division of animal cells, cytoplasmic streaming in plant cells
- Muscle contraction
24
Q
Intermediate filaments
A
- medium sized filaments in cytoskeleton
- made of several different proteins
- coiled protein structure
- cell shape, anchorage of nucleus and other organelles, formation of nuclear lamina
25
Extracellular matrix
```
(ECM)
•outside the cell
•gives strength, structural support and organization
•important in cell signaling
•built by endomembrane system
•proteins are embedded in cell membrane
```
26
Adhesive proteins
Proteins in the ECM
•Fibronectin: connects cells to EVM
•Laminin: connects cells to ECM in basal lamina
27
Structural ECM proteins
1. Collagen: large fibers, many types, strength
| 2. Elastin: elastic fibers in ECM
28
Basal lamina
base layer that cells stick to
29
Animal cell attachment
1. Tight junctions: hold cells together, nothing passes between cells, stitching pattern, different proteins than desmosomes
2. Gap junction: allows small molecules and ions to flow between cells
3. Desmosome: Parts of cytoskeleton are attached, gives tissues strength, keeps cells together, protein-protein interaction, no passing through
30
Plant cell attachment
1. Middle lamella: Sugary, sticky, glue like substance secreted by plant cells that holds cells together
2. Plasmodesmata: Leaves gaps, tubes that penetrate two cells holding them together, substances can travel through the tubes
31
Attachment in bacteria
They fibriae, and a pilus/pilii
32
How do vesicles move within cells?
Motor proteins “walk” vesicles along microtubules, powered by hydrolyzing ATP
33
What happens when ATP is hydrolyzed?
A phosphate group is removed, and it becomes ADP
34
Microtubule organizing centers
Basal bodies and centrioles
35
How are cilia and flagellum moved?
They are controlled by microtubules in doublets, attached by motor proteins.
36
Centrioles
microtubule organizing centers that also organize spindle fibers for mitosis in eukaryotes
37
How are cilia and flagella attached to the cell?
the are extensions of the cell that are completely enclosed by cell membranes
38
Genome
all of the DNA in a cell
39
Proteome
proteins found in a specific type of cell
40
Which cells in the human body have different genomes?
red blood cells have different genomes from the rest of the body
41
Differentiation
When stem cells turn into a specific cell type as a result of external signals. This process is irreversible
42
What are most cell signals?
chemical signals
43
What level of variety is found in cell signaling across all domains of life?
There is some variety, but overall similar
44
Steps of cell signaling
1. Reception
2. Transduction
3. Response
45
How do bacteria search for food?
They “run and tumble”. The swim in a direction, then let their flagella spread out. This process is repeated until food/signals are found
46
How does transduction work?
When a signal is received, the receptor changes shape on the inside of the cell, causing further downstream changes
47
What is true of all signal receptors?
* the signal is specific
* bind of signal causes shape change to receptor
* most signal receptors are plasma membrane proteins
48
Steroid receptors
* Cell signal receptors inside the cell
* Go into nucleus after signal binding
* acts as a transcription factor
49
Transcription factors
something that interacts directly with DNA
50
G protein-coupled receptor process
1. Signaling molecule binds to G protein-coupled receptor
2. G-protein detaches from G protein-coupled receptor and travels to inactive enzyme, this is powered by hydrolysis of ATP
3. Inactive enzyme is activated when G protein attaches to it
4. G-protein heads back to G-protein coupled receptor
51
Types of metabolism
Catabolic: breaks molecules down via hydrolysis, releases energy, cellular respiration
Anabolic: Builds molecules via dehydration, consumes energy, protein synthesis, photosynthesis
52
First law of thermodynamics
Conservation of energy, energy can not be created or destroyed
53
Second law of thermodynamics
Every energy transfer increases entropy of the universe, aka heat is lost in every reaction
54
free energy
energy that can do work when pressure and temp are uniform(🔼G)
55
What do high and low levels of free energy indicate
High: less stable, greater work capacity
Low: More stable, less work capacity
56
Exergonic/endergonic reactions
Exergonic: net release of free energy(🔼G<0), spontaneous, catabolic
Endergonic: Absorbs free energy from surroundings, not spontaneous, (🔼G>0), anabolic,
57
ATP components and name
Name: Adenosine triphosphate
Components: ribose, adenine(a nitrogenous base), and 3 phosphate groups
58
ATP hydrolysis
Terminal P from P tail is removed, energy comes from moving to a state of lower free energy
59
How does ATP power the cell?
Coupling endergonic and exergonic reactions
60
Types of work a cell does
1. Chemical
2. Transport
3. Mechanical
61
How can reactions be coupled in metabolic pathways?
Energy from an exergonic reaction can be used as activation energy for an endergonic reaction
62
How is ATP recycled
ADP can be made back into ATP
63
How do enzymes speed up reactions?
The decrease the activation energy of a reaction by
1. orienting substrates correctly
2. straining substrate bonds
3. providing a favorable microenvironment
4. covalently bonding to the substrate
64
Active site
Region of the enzyme where the substate fits
65
Things that change the shape of an enzyme
1. Cofactors: inorganic
| 2. Coenzymes: organic
66
Competitive vs noncompetitive inhibitors
Competitive: bind to active site of enzyme, competing with substrate
Noncompetitive: bind to a part of the enzyme other than the active site, causing the enzyme to change shape, making the active site less effective
67
Allosteric activator/inhibitor
Changes shape or stability of the enzyme by binding to a location on the enzyme other than the active site
68
feedback inhibition
When the end product of a metabolic pathway inhibits enzymes of the initial substrate so that the end product is not overproduced. When the end product is used by the cell, more is allowed to be produced
69
Parts of endomembrane system
Nucleus, ER, golgi, membrane
70
Myosin
protein activate in contraction of muscle tissue. They have alternating filaments with actin filaments. They contain myosin heads that move along actin filaments using ATP. The filaments are pulled over myosin heads causing contraction
71
Cristae
Part of inner membrane of mitochondria that fold to increase surface area
71
Nuclear lamina
gives support to nucleus, gives it spherical shape and strength, lies in the inside of the nuclear membrane to make it sturdy, like a cytoskeleton of the nucleus, fibers run in a matrix pattern to give it shape/support
