Bio Lect2 Flashcards
1
Q
What are atoms?
A
Atoms are the smallest particles that retain the properties of an element
2
Q
Which elements are considered essential?
A
Examples include carbon and oxygen
3
Q
What are the sub-atomic particles that make up atoms?
A
Protons, neutrons, electrons
4
Q
How is the elemental property of an atom determined?
A
By its atomic number, which equals the number of protons
5
Q
What is the charge of the cloud surrounding the nucleus of an atom?
A
Negative charge due to electrons
6
Q
What components make up the nucleus of an atom?
A
Protons and neutrons
7
Q
What is the typical relationship between protons and neutrons in most atoms?
A
Most atoms have equal numbers of protons and neutrons
8
Q
What is unique about some isotopes?
A
Some isotopes have additional neutrons
9
Q
Provide an example of an isotope and its composition.
A
Carbon-14 has 6 protons and 8 neutrons
10
Q
What is the purpose of carbon dating?
A
To date materials based on the breakdown of carbon-14
11
Q
What determines chemical bonding?
A
Physical chemistry of an atom is determined by its complement of electronic charge (e) and their distribution
12
Q
How do electrons distribute around the atomic nucleus?
A
Electrons distribute around the atomic nucleus in spaces described as ‘shells’ and ‘orbitals’ which define the probability distribution of an electron (or electrons)
13
Q
What are the components of the first shell?
A
1s orbital
14
Q
What are the components of the second shell?
A
2s orbital and three 2p orbitals
15
Q
How do electrons move between shells?
A
Electrons move between shells only on input/release of energy
16
Q
Which shell has the highest energy level?
A
Third shell
17
Q
Which shell has the lowest energy level?
A
First shell
18
Q
Fill in the blank: Electrons move between shells only on _______ or _______ of energy.
A
input/release
19
Q
What are the energy levels of the shells from lowest to highest?
A
- First shell (lowest energy level)
- Second shell (higher energy level)
- Third shell (highest energy level)
20
Q
What is an s orbital?
A
A type of atomic orbital that can hold a maximum of two electrons.
21
Q
What is the 2s orbital?
A
The s orbital in the second energy level.
22
Q
How many 2p orbitals are there?
A
Three 2p orbitals.
23
Q
What is the relationship between the first and second shells in terms of energy levels?
A
The second shell has a higher energy level than the first shell.
24
Q
What is the lowest energy level shell?
A
First shell.
25
What is the atomic nucleus?
The central part of an atom, containing protons and neutrons.
26
What orbitals are present in the first and second energy levels?
1s, 2s, and 2p orbitals.
27
What determines bond formation?
Bonds arise when atoms share or exchange electrons to fill or empty shells.
28
What are the most stable atomic states characterized by?
Paired electrons and filled electron shells.
29
Fill in the blank: Two hydrogen atoms can form a _______.
single bond.
30
How do two oxygen atoms bond?
They share two pairs of electrons to form a double bond.
31
What is the molecular formula for water?
H2O.
32
What atoms are joined by covalent bonds in a water molecule?
Two hydrogen atoms and one oxygen atom.
33
What is the molecular formula for methane?
CH4.
34
True or False: Atoms with unpaired electrons and partially-filled outer shells react to fill or empty the shell.
True.
35
What type of bond arises when atoms exchange electrons?
Ionic bonds
## Footnote
Ionic bonds are crucial for forming compounds essential for life.
36
What is bond capacity also known as?
Atomic valence
## Footnote
Atomic valence indicates the number of bonds an atom can form.
37
What determines compound structures?
Compound structure is determined by the valence shells in the bonds. E.g. determines protein structure
38
Which bonds are important for life?
Hydrogen bonds and weaker interactions like Van Der Waals.
Hydrogen bonds-partial charge interactions between polar molecules.
Van Der Waals interactions arise from locally induced dipoles between atoms in very close proximity.
39
Why is water universal solvent for life?
Water (H2O) is a polar molecule and forms hydrogen bonds.
Hydrogen bonds explains:
- cohesive and adhesive properties
- also high specific heat (hence a good insulator)
Also The polarity of water allows:
-Solvation interactions with charged (ionic) compounds (forms ‘hydration’ shells)
-Solvation interactions with uncharged polar compounds
-High reactivity with many other transition metals/atom
40
What does hydrogen bond give water?
Hydrogen bonds give water its crystal structure and ridgidity in ice and enable plant transpiration.
41
What are membranes
Membranes are phospholipid polymers of fatty acids, glycerol,phosphate and a terminal amine or alcohol group
42
What is the definition of membranes?
Membranes are phospholipid polymers of fatty acids, glycerol, phosphate, and a terminal amine or alcohol group.
## Footnote
Membranes play a crucial role in cell structure and function.
43
What is a glycerol ester linkage?
A glycerol ester linkage is a bond formed between glycerol and fatty acids in phospholipids.
## Footnote
This linkage is significant for the formation of membrane structures.
44
What are the components of phosphatidyl choline?
Phosphatidyl choline comprises:
* Choline
* A phosphate linkage to glycerol
* Two fatty acids
## Footnote
Phosphatidyl choline is a major component of biological membranes.
45
What characterizes the hydrophilic head group of a phospholipid?
The hydrophilic head group interacts with water and is polar.
## Footnote
This property is essential for membrane formation in aqueous environments.
46
What characterizes the hydrophobic tail groups of a phospholipid?
The hydrophobic tail groups do not interact with water and are nonpolar.
## Footnote
This property contributes to the formation of the lipid bilayer.
47
Fill in the blank: Membranes are polymers of _______.
[phospholipids]
48
True or False: Membranes are composed solely of proteins.
False
## Footnote
Membranes are primarily composed of phospholipids, not just proteins.
49
What is the structural significance of the hydrophilic and hydrophobic regions in membranes?
The hydrophilic regions face outward towards the water, while the hydrophobic regions face inward, away from the water.
## Footnote
This arrangement is crucial for membrane stability and function.
50
What are membranes?
Membranes are structures formed by phospholipids that are amphipathic in nature.
51
What are the two main arrangements of phospholipids in water?
Monolayers and bilayers.
52
What is the characteristic of phospholipid molecules?
They are amphipathic, meaning they have both hydrophilic and hydrophobic parts.
53
In a lipid bilayer, which part faces water?
The hydrophilic head.
54
In a lipid bilayer, which part faces oil?
The hydrophobic tail.
55
Fill in the blank: Simple detergents are salts of fatty acids, which retain this _______ and are able to interact and dissolve other organic compounds.
amphipathicity
56
What is a liposome?
A spherical structure formed by lipid bilayers.
57
What is a micelle?
An aggregate of amphipathic molecules in a colloidal solution.
58
What is the role of the hydrophobic tail in phospholipids?
To face away from water, interacting instead with oils or fats.
59
What is a monolayer?
A single layer of phospholipids arranged with their hydrophilic heads in contact with water.
60
True or False: The hydrophilic part of phospholipids is repelled by water.
False
61
What does amphipathic mean in the context of membrane phospholipids?
Having both hydrophilic (water-attracting) and hydrophobic (water-repelling) regions.
62
Why are membranes important?
Membranes are important because they compartmentalize metabolic activities, separate and protect cellular components, provide a scaffold for signaling, and serve as a medium for cellular energy generation.
## Footnote
These functions arise from the immiscibility of water and membranes.
63
What is the diffusion rate of sucrose across membrane bilayers?
Sucrose diffusion across membrane bilayers is 1,000,000-fold slower (10^-6 less) compared to other substances.
## Footnote
This significantly low diffusion rate highlights the selective permeability of cellular membranes.
64
Fill in the blank: Cellular membranes function to _______ metabolic activities.
[compartmentalize]
65
True or False: Membranes protect cellular components.
True
66
What role do membranes play in cellular signaling?
Membranes provide a 'scaffold' for signaling.
## Footnote
This scaffolding is essential for various signaling pathways and cellular communication.
67
List the key functions of cellular membranes.
* Compartmentalize metabolic activities
* Separate/protect cellular components
* Provide a scaffold for signaling
* Serve as a medium for cellular energy generation
68
Fill in the blank: The immiscibility of _______ and membranes contributes to their function.
[water]
69
What do diffusion rates mean?
The speed at which molecules or particles move from an area of high concentration to an area of low concentration
## Footnote
Diffusion rates are influenced by factors such as temperature, size of molecules, and concentration gradient.
70
How long does it take sucrose to diffuse a distance x?
The time varies based on factors such as concentration gradient and temperature
## Footnote
Specific equations can be used to calculate diffusion time under given conditions.
71
What limits membrane dimensions and cell size?
The physical properties of diffusion of compounds in water
## Footnote
As diffusion rates dictate how quickly substances can enter or exit cells, they play a crucial role in cellular function.
72
What do biological membranes hold?
Charge
73
What drives the diffusion of ions?
Both chemical and electrical gradients
74
What does selective diffusion across semi-permeable membranes generate?
A small ion (charge) imbalance
75
What does the Nernst Equation describe?
The equilibrium between chemical and electrical forces on a charged molecule (ion)
76
Fill in the blank: The Nernst Equation relates to the equilibrium between chemical and _______ forces.
Electrical
77
True or False: With no channels, there is a diffusion force.
False
78
What happens with no channels in a biological membrane?
There is no diffusion force
79
What do biological membranes hold?
Charge
## Footnote
This is essential for the generation of ion gradients.
80
What is the process of generating biological energy through ion gradients across membranes called?
Bioenergetics
## Footnote
This process is crucial for cellular functions.
81
How can the voltage across the cell membrane be measured?
Using microelectrodes implanted in cells
## Footnote
This method allows for precise measurement of membrane potential.
82
What can be used to measure voltage across endomembranes like mitochondria and lysosomes?
Voltage-sensitive dyes
## Footnote
These dyes provide a visual representation of voltage changes.
83
True or False: The voltage across biological membranes is not important for cellular energy.
False
## Footnote
Voltage is critical for maintaining ion gradients that drive energy production.
84
Fill in the blank: Ion gradients across membranes are used to generate _______.
[biological energy]
## Footnote
This is a fundamental concept in bioenergetics.
85
What is the significance of measuring voltage across membranes?
It helps understand bioenergetics and cellular functions
## Footnote
Monitoring membrane voltage is essential for studying cell physiology.
86
Where are membranes found?
In all organelles of eukaryotic cells
## Footnote
Membranes serve as delimiters for organelles, allowing for compartmentalization within the cell.
87
Membranes are found in _______.
all organelles of eukaryotic cells
88
What is the primary function of membranes in eukaryotic cells?
Delimiting organelles
89
What is required to obtain a picture of an electron microgram of a stem cell?
You need to take the tissue and kill it.
90
What is the first step after obtaining the tissue for electron microscopy?
Exchange the water for some solvent.
91
What must be introduced into the solvent during the preparation of a sample for electron microscopy?
Plastic.
92
What happens to the plastic after it is introduced into the solvent?
It hardens.
93
What is done with the hardened plastic block in the electron microscopy process?
It is stained with an electron dense stain like osmium.
94
How is the hardened plastic block prepared for imaging in electron microscopy?
It is cut into really thin layers using a diamond knife.
95
What is placed under a grid and vacuum during the imaging process?
The thin layers cut from the hardened plastic block.
96
What is used to create the image of the cell in electron microscopy?
An electron beam.
97
How long do you have to capture the image before it burns down?
2-3 minutes.
98
What type of picture does electron microscopy provide?
A static picture of the cell.
99
What happens to a molecule in the ground state when it absorbs a photon?
It is raised to an excited state, boosting one of the molecule's electrons to an orbital farther from the nucleus.
## Footnote
This process involves energy absorption and results in the electron moving to a higher energy level.
100
What is the term for the state of a molecule with the lowest energy?
Ground state
## Footnote
The ground state is the baseline energy level of a molecule, where it is most stable.
101
What is emitted when an electron relaxes back to the ground state?
Energy is released as light.
## Footnote
This light emission can be observed as fluorescence.
102
Fill in the blank: The absorption of a photon _______ electrons.
excites
## Footnote
Excitation refers to the process of raising electrons to higher energy levels.
103
What is fluorescence?
The light absorbed by a pigment is re-emitted at a longer wavelength.
## Footnote
Fluorescence is a specific type of photoluminescence.
104
What diagram is used to represent the electronic transitions of molecules during fluorescence?
Jablonski diagram
## Footnote
The Jablonski diagram illustrates the energy levels and transitions of electrons in molecules.
105
True or False: The excited state of a molecule is a stable state.
False
## Footnote
The excited state is generally less stable than the ground state and will eventually return to the ground state.
106
What does the term 'photon' refer to?
A particle of light or electromagnetic radiation.
## Footnote
Photons are fundamental to the processes of absorption and emission in fluorescence.
107
What is the relationship between excited state and energy?
The excited state possesses more energy than the ground state.
## Footnote
Energy is required to excite electrons, moving them to higher energy levels.
108
What occurs during the process of absorption?
A molecule absorbs energy from a photon, causing electronic excitation.
## Footnote
This process is crucial for photosynthesis and various photochemical reactions.
109
Fill in the blank: The _______ is the region around the nucleus where electrons are likely to be found.
orbital
## Footnote
Orbitals are defined regions of space around the nucleus where electrons reside.
110
What is the source organism for Green Fluorescent Protein (GFP)?
Aquoria victoria (jellyfish)
## Footnote
GFP is derived from the jellyfish Aquoria victoria, which is known for its bioluminescent properties.
111
What type of proteins are Green Fluorescent Protein (GFP) categorized as?
Intrinsically-fluorescent proteins
## Footnote
Intrinsically-fluorescent proteins are capable of emitting fluorescence without the need for additional substrates.
112
True or false; Aquoria Victoria (jellyfish) includes genes for intrinsically- fluorescent proteins.
True
113
What does GFP stand for?
Green Fluorescent Protein
## Footnote
GFP is a protein that exhibits fluorescence when exposed to ultraviolet light.
114
In which types of organisms is GFP expressed?
In plants and animals
## Footnote
GFP is commonly used in molecular biology to study gene expression and protein localization.
115
True or False: GFP only fluoresces under visible light.
False
## Footnote
GFP fluoresces under ultraviolet light.
116
Fill in the blank: GFP is used as a _______ in biological research.
[fluorescent marker]
## Footnote
It allows for visualization of specific proteins within cells.
117
What is the significance of GFP in scientific research?
It allows researchers to visualize and track proteins in living organisms
## Footnote
This has applications in genetics, developmental biology, and cell biology.
118
What is a confocal image?
A stack of images, put in rotation to give a sense of the 3-dimensional structure
## Footnote
Confocal imaging is often used in microscopy to enhance the optical resolution and contrast of a micrograph by using a spatial pinhole to block out-of-focus light.
119
True or False: Endoplasmic reticulum is highly mobile
True
120
What does the mobility of endoplasmic reticulum depends on?
The mobility depends upon the interactions of the endoplasmic reticulum with the cytoskeleton
121
What does GFP provide to aquoria Victoria?
Phosphorescence
## Footnote
GFp refers to Green Fluorescent Protein, which is responsible for the light-emitting properties in these organisms.
122
What type of molecules are involved in the phosphorescent property of aquoria Victoria?
Molecules that absorb and emit light fluorescence without co-factors
## Footnote
These molecules operate independently of additional substances to produce light.
123
What is coded entirely in the amino acid structures of molecules like GFP?
Light absorption and emission
## Footnote
This indicates that the ability to absorb and emit light is inherent to the protein's structure.
124
What can be done by fusing the gene that codes for GFP to the protein of interest?
Express that protein wherever you want
## Footnote
This technique allows researchers to track and study specific proteins in living organisms.
125
What type of microscopy can be used to ask questions in living tissue after expressing a protein with GFP?
Conical microscopy
## Footnote
This type of microscopy allows for detailed imaging of biological samples.
126
What is SYP121?
A trafficking protein
## Footnote
SYP121 is involved in the transport of proteins within cells.
127
What happens to GFP in secGFP-transfected leaves?
GFP is normally secreted
## Footnote
This indicates that the protein is being properly trafficked in the plant system.
128
What is observed when GFP accumulates in the ER and Golgi?
It occurs when co-transfected with SYP121
## Footnote
This suggests a role of SYP121 in the retention or processing of GFP in these organelles.
129
Fill in the blank: GFP accumulates in the _______ and Golgi when co-transfected with SYP121.
[Endoplasmic reticulum]
130
What is the function of SYP 121?
It's a vehicle trafficking protein. It also regulates ion channels at the plasma membrane.
131
Is the Golgi an interconnected network in animal cells?
No
132
What type of membrane do chloroplasts and mitochondria have?
Double membrane consisting of an outer and inner membrane
133
What unique feature do chloroplasts and mitochondria possess regarding their genetic material?
They carry their own DNA
134
What process do chloroplasts and mitochondria use for division and replication?
Fission
135
What is the significance of the double membranes in chloroplasts and mitochondria?
Suggests endosymbiont progenitor
136
True or False: Chloroplasts and mitochondria undergo independent division.
True
137
What organelles communicate within cells?
Chloroplasts
138
What structures connect chloroplasts to each other?
Stromules
139
Where does communication between chloroplasts occur?
Within cells
140
Fill in the blank: Chloroplasts communicate within cells through _______.
Stromules
141
What is the role of stromules?
They facilitate communication between chloroplasts.
142
What is the structure of the endoplasmic reticulum space?
Interconnected
## Footnote
The endoplasmic reticulum (ER) is a network of membranes within the cell.
143
What happens to fluorescence when high intensity light is used?
Burn out the fluorescence
## Footnote
This leads to molecules losing their ability to absorb light and fluoresce.
144
True or False: The endoplasmic reticulum is a disconnected structure.
False
## Footnote
The endoplasmic reticulum space is interconnected.
145
What is one possible explanation for the loss of fluorescence in the ER?
Increased mobility within the ER
