Cells Flashcards
(94 cards)
1
Q
What is the overall function of the nucleus?
A
DNA replication and transcription (mRNA synthesis)
The nucleus contains the genetic code for the cell.
2
Q
What structures are found within the nucleus?
A
- Nuclear envelope
- Nuclear pores
- Nucleoplasm
- Chromosomes
- Nucleolus
3
Q
What is the function of the nucleolus?
A
RNA production and ribosome assembly
4
Q
What are the two types of endoplasmic reticulum?
A
- Rough endoplasmic reticulum (RER)
- Smooth endoplasmic reticulum (SER)
5
Q
What occurs in the rough endoplasmic reticulum?
A
Protein synthesis
Folds and processes the proteins made at the ribsomes on them
6
Q
What is the function of the smooth endoplasmic reticulum?
A
Synthesis and storage of lipids and carbohydrates
7
Q
What is the structure and function of the Golgi apparatus?
A
Folded membrane structure that modifies, packages, and transports proteins and lipids
8
Q
What are lysosomes and their primary function?
A
Bags of digestive enzymes involved in hydrolyzing materials, often during phagocytosis
9
Q
What is the primary role of mitochondria?
A
Site of aerobic respiration and ATP production
10
Q
What is unique about the DNA found in mitochondria?
A
It is similar to prokaryotic DNA and codes for enzymes needed in respiration
11
Q
What is the difference between 70s and 80s ribosomes?
A
70s ribosomes are found in prokaryotic cells and mitochondria; 80s ribosomes are found in eukaryotic cells
12
Q
What is the function of the vacuole in plant cells?
A
Provides turgidity, support, and temporary storage for sugars and amino acids
13
Q
What is the function of chloroplasts?
A
Site of photosynthesis
14
Q
What structures are involved in photosynthesis within chloroplasts?
A
- Thylakoid membranes (site of light-dependent reactions)
- Stroma (site of light-independent reactions)
15
Q
What is the composition of cell walls in plants and fungi?
A
- Cellulose in plants
- Chitin in fungi
16
Q
What is the function of the plasma membrane?
A
Controls entry and exit of substances in cells
17
Q
What are the key differences between prokaryotic and eukaryotic cells?
A
- Prokaryotic cells are smaller
- Prokaryotic cells lack membrane-bound organelles
- Prokaryotic cells have 70s ribosomes
- Prokaryotic cells have circular DNA in the cytoplasm
18
Q
What are the main components of a virus?
A
- Genetic material
- Capsid
- Attachment proteins
19
Q
True or False: Viruses are cellular and living organisms.
A
False
20
Q
What is the purpose of advances in microscopy for studying cells?
A
To discover internal structures and organelles
21
Q
What are the three main types of microscopes?
A
- Optical microscopes
- Transmission electron microscopes
- Scanning electron microscopes
22
Q
Fill in the blank: The resolution of a microscope is the minimum distance between two objects in which they can still be viewed as _______.
A
separate
23
Q
What determines the resolution of optical microscopes?
A
Wavelength of light
24
Q
What determines the resolution of electron microscopes?
A
Wavelength of the beam of electrons
25
What is the advantage of electron microscopes over optical microscopes?
Higher resolution due to shorter wavelength of electrons
26
What type of images do optical microscopes produce?
Color images and can view living samples
27
What type of images do electron microscopes produce?
Black and white images; cannot observe living samples
28
What is the key difference between transmission and scanning electron microscopes?
Transmission produces 2D images; scanning produces 3D images
29
What is the formula for calculating magnification?
Image size = Actual size × Magnification
30
What conditions must be met for cell fractionation?
* Cold
* Isotonic
* Buffered
31
What is the first step in cell fractionation?
Homogenization (breaking open the cells)
32
What is the purpose of using a buffered solution during cell fractionation?
To prevent changes in pH that could damage organelles
33
What is the two-step process of cell fractionation?
Homogenization and Ultra centrifugation
## Footnote
Homogenization involves breaking open the cells, and ultra centrifugation isolates organelles based on density.
34
What conditions must be met during homogenization?
The solution must be cold, isotonic, and buffered
## Footnote
These conditions prevent damage to organelles during cell breaking.
35
What is differential centrifugation?
A process where organelles are separated based on their densities by spinning at different speeds
## Footnote
This allows for the formation of pellets from the most dense organelles.
36
In the first centrifugation, which organelle is the most dense?
Nuclei
## Footnote
Nuclei are isolated first, followed by chloroplasts, mitochondria, lysosomes, endoplasmic reticulum, and ribosomes in order of decreasing density.
37
What are the stages of the eukaryotic cell cycle?
Interphase, mitosis, cytokinesis
## Footnote
Interphase includes G1, S, and G2 phases.
38
What happens during the S phase of the cell cycle?
DNA replication occurs
## Footnote
This is a critical step for ensuring each new cell receives a complete set of DNA.
39
What is the purpose of G2 phase in the cell cycle?
Further growth and error checking before mitosis
## Footnote
Cells that have errors in DNA replication may be destroyed.
40
What are the four key stages of mitosis?
Prophase, Metaphase, Anaphase, Telophase
## Footnote
Collectively referred to as PMAT.
41
What type of cells are produced by mitosis?
Genetically identical diploid cells
## Footnote
Mitosis is used for growth and repair.
42
What is the role of spindle fibers during mitosis?
They attach to centromeres and pull chromatids apart
## Footnote
This action is crucial for separating genetic material into daughter cells.
43
What is cytokinesis?
The division of the cytoplasm to create two new cells
## Footnote
This occurs after mitosis.
44
How do prokaryotic cells divide?
By binary fission
## Footnote
This involves replication of circular DNA and division of cytoplasm.
45
What is the fluid mosaic model?
A model describing the structure of cell membranes composed of phospholipids and proteins
## Footnote
It illustrates the fluid nature and variety of components in the membrane.
46
What is the function of integral proteins in the cell membrane?
They act as protein channels or carriers for transporting molecules
## Footnote
Integral proteins span the bilayer and facilitate the movement of substances.
47
What does partially permeable membrane mean?
Only lipid-soluble substances and small molecules can pass through
## Footnote
Larger or polar molecules require facilitated diffusion or active transport.
48
What is simple diffusion?
The net movement of molecules from higher to lower concentration without ATP
## Footnote
This process continues until equilibrium is reached.
49
Define osmosis.
The movement of water from an area of higher water potential to lower water potential across a partially permeable membrane
## Footnote
Water potential is measured in kilopascals.
50
What is the difference between isotonic, hypotonic, and hypertonic solutions?
* Isotonic: same water potential as the cell
* Hypotonic: more positive water potential than the cell
* Hypertonic: more negative water potential than the cell
## Footnote
These terms describe the relative concentration of solutes in solutions compared to the cell.
51
What happens to animal cells in a hypertonic solution?
They shrivel or crenate due to water loss
## Footnote
This occurs because water moves out of the cell by osmosis.
52
What is active transport?
The movement of substances from lower to higher concentration requiring metabolic energy
## Footnote
It involves carrier proteins and is selective.
53
What is co-transport?
A type of active transport where glucose or amino acids are transported with sodium ions
## Footnote
This process is crucial for nutrient absorption in the gut.
54
What is co-transport in the context of glucose absorption?
Co-transport involves the simultaneous transport of glucose or amino acids with sodium ions into epithelial cells of the ilium.
55
What creates the concentration gradient for sodium ions in epithelial cells?
Active transport of sodium ions out of the epithelial cell into the capillaries creates a lower concentration of sodium ions within the epithelial cells.
56
What role do co-transporter proteins play in glucose absorption?
Co-transporter proteins allow sodium ions to diffuse into epithelial cells while simultaneously transporting glucose or amino acids against their concentration gradients.
57
How is glucose transported from the epithelial cell into the blood?
Glucose moves by facilitated diffusion from the epithelial cell into the blood.
58
What adaptations can cells have for rapid transport across membranes?
Cells may have increased surface area (e.g., microvilli) or an increased number of protein channels and carrier molecules.
59
What is the primary function of the immune system's lymphocytes?
Lymphocytes identify and destroy foreign pathogens and harmful substances while avoiding damage to self-cells.
60
How do lymphocytes distinguish between self and non-self cells?
Lymphocytes recognize specific surface molecules, usually proteins, that have unique 3D structures indicating self or non-self.
61
What is an antigen?
An antigen is a molecule that generates an immune response, typically located on the surface of pathogens.
62
What is antigen variability?
Antigen variability refers to the frequent mutations in pathogen DNA that change the shape of the antigen, potentially leading to loss of immunity.
63
Why is a new flu vaccine created every year?
The influenza virus mutates rapidly, changing its antigens, necessitating a new vaccine to account for these changes.
64
What are the two types of immune responses of white blood cells?
Specific and non-specific responses.
65
What is phagocytosis?
Phagocytosis is a non-specific immune response where phagocytes engulf and destroy foreign cells.
66
What enzymes do phagocytes use to destroy pathogens?
Phagocytes use lytic enzymes, such as lysozyme, to hydrolyze and break down pathogens.
67
Where do T lymphocytes mature?
T lymphocytes mature in the thymus.
68
What is the role of antigen presenting cells (APCs)?
APCs present non-self antigens on their surface, triggering an immune response from T cells.
69
What happens once a T cell binds to an antigen presented by an APC?
The T cell is activated and begins to divide by mitosis, creating many cloned cells.
70
What are the different types of T cells produced after clonal expansion?
* Helper T cells
* Cytotoxic T cells
* Memory T cells
71
What do cytotoxic T cells do?
Cytotoxic T cells destroy abnormal or infected cells by releasing perforin to create pores in the cell membrane.
72
What is the humoral response?
The humoral response involves B lymphocytes and the production of antibodies.
73
What do B cells do when they encounter an antigen?
B cells take in the antigen by endocytosis and present it on their surface.
74
What is the difference between plasma cells and memory B cells?
Plasma cells produce antibodies, while memory B cells can rapidly divide into plasma cells upon re-exposure to the same antigen.
75
What is active immunity?
Active immunity occurs when memory B cells allow for rapid antibody production upon re-infection.
76
What is the primary response in the immune system?
The primary response is the initial slower antibody production when first exposed to a new antigen.
77
What is the secondary response in the immune system?
The secondary response is the rapid and larger antibody production upon subsequent exposure to the same antigen.
78
What is the structure of antibodies?
Antibodies are quaternary structure proteins made up of four polypeptide chains.
79
What is the primary response in the immune system?
The primary response is when antibodies are created rapidly and in larger numbers after a second exposure to a pathogen.
## Footnote
This response is characterized by the body's ability to remember the pathogen and react swiftly upon re-exposure.
80
What are antibodies an example of?
Antibodies are an example of quaternary structure proteins made up of four polypeptide chains.
## Footnote
The structure includes variable and constant regions, heavy and light chains.
81
What is the function of the variable region of an antibody?
The variable region is where the antibody binds to specific shaped antigens.
## Footnote
This specificity is crucial for the immune response.
82
What is agglutination in the context of antibodies?
Agglutination is the clumping together of antibodies and antigens.
## Footnote
This process aids phagocytes in locating and destroying pathogens more efficiently.
83
Define passive immunity.
Passive immunity is when antibodies are introduced to the body without the individual producing them.
## Footnote
Examples include antibodies passed from mother to fetus through the placenta or breast milk.
84
What is active immunity?
Active immunity is when the immune system creates its own antibodies following exposure to a pathogen.
## Footnote
This can be natural (from infection) or artificial (from vaccination).
85
How do vaccines work?
Vaccines introduce small amounts of weakened or dead pathogens or antigens to activate B cells, leading to clonal expansion and differentiation.
## Footnote
This process results in the production of memory B cells that provide long-term immunity.
86
What is herd immunity?
Herd immunity occurs when a sufficient portion of the population is vaccinated, preventing the spread of pathogens to those who cannot be vaccinated.
## Footnote
This provides protection for vulnerable individuals.
87
What are the four key components of HIV?
* Core (RNA and reverse transcriptase)
* Capsid (outer protein)
* Envelope (host cell membrane)
* Protein attachments (for host cell attachment)
## Footnote
These components are essential for the virus's replication and infection process.
88
What happens when HIV infects a helper T cell?
HIV attaches to the CD4 protein, fuses with the cell membrane, and injects its RNA and reverse transcriptase into the host cell.
## Footnote
The RNA is then converted to DNA, allowing viral replication.
89
What distinguishes someone who is HIV positive from someone with AIDS?
An HIV positive individual may not show symptoms, while AIDS is characterized by the immune system's failure due to HIV's destruction of helper T cells.
## Footnote
The destruction of the immune system leads to vulnerability to other infections.
90
What are monoclonal antibodies?
Monoclonal antibodies are identical antibodies produced from a single clone of cells, designed to bind to specific antigens.
## Footnote
They are used in medical treatments and diagnostics.
91
What is direct monoclonal antibody therapy?
Direct monoclonal antibody therapy uses antibodies designed to bind to antigens on cancer cells, preventing their growth.
## Footnote
This method targets cancer cells without harming normal cells.
92
What is indirect monoclonal antibody therapy?
Indirect monoclonal antibody therapy involves antibodies attached to drugs that target cancer cells for treatment.
## Footnote
This method reduces side effects compared to traditional chemotherapy.
93
What is the purpose of the ELISA test?
The ELISA test is used for medical diagnosis, detecting the presence of specific antigens or antibodies in a sample.
## Footnote
It is commonly used in pregnancy tests and tests for viral diseases.
94
What ethical issues surround monoclonal antibody production?
The production of monoclonal antibodies involves the use of animals, leading to ethical debates about the justification of animal use for human medical benefits.
## Footnote
Concerns include animal discomfort, harm, and death.
