Topic 2 Cells: Organelles Flashcards
1
Q
- Nucleus: bound by double layer nuclear envelope with nuclear pores for transport (mRNA, ribosome, subunits, dNTPs, RNA polymerase, and histones)
A
Nucleus
2
Q
- General packaging structure of DNA around proteins in eukaryotes
- Tightness depends on cell stage
A
Chromatin
3
Q
- Tightly condensed chromatin when the cell is ready to divide
A
Chromosomes
4
Q
- Serve to organize DNA
- Coils around DNA into bundles called nucleosomes (wrapped around 8 histone proteins)
A
Histones
5
Q
- Inside of the nucleus
- Serves as the site of ribosome synthesis which are synthesized using rRNA and ribosomal proteins imported from the cytoplasm
- Once ribosome subunits are formed, they are exported to the cytoplasm for final assembly to a ribosome
A
Nucleolus
6
Q
- Dense fibrillar network inside the nucleus of eukaryotic cells
- Consists of intermediate filaments + membrane proteins
- Provides mechanical support
- Helps regulate DNA replication, cell division, and chromatin organization
A
Nuclear Lamina
7
Q
- Within prokaryotes
- Contains most of the cells genetic material
A
Nucleoid
8
Q
- This is an area, not a structure
- Contains cytosol and organelles
- Metabolic activity and transport occur here
- Cytoplasmic streaming: streaming movement
A
Cytoplasm
9
Q
- Cytosol doesn’t include the components suspended within the gel-like substance, it is just the gel-like substance
- Cytoplasm: jello + candy
- Cytosl: just jello
A
Cytosol/Cytoplasmic Matrix
10
Q
- Organelles made of rRNA
- Make proteins
- Composed of two subunits:
1. Eukaryotes: 60S + 40S = 80 S
2. Prokaryotes: 50S + 30S = 70S - The subunits are produced inside the nucleolus and moved to cytoplasm where they create a single large ribosome
- Larger S value means heavier molecule
A
Ribosomes
11
Q
Rough ER and Smooth ER
A
Endoplasmic Reticulum
12
Q
- Studded with ribosomes, creates glycoproteins by attaching polysaccharides to polypeptides as they are assembled to ribosomes; in eukaryotes the rough ER is continuous with outer nuclear membrane
A
Rough ER
13
Q
- Without ribosomes, serves to synthesize lipids and steroid hormones for export
- In liver cells, it functions to break down toxins, drugs, and toxic by-products from cellular reactions
- Smooth and striated muscle have smooth ER’s called sarcoplasmic reticulum that store and release ions
A
Smooth ER
14
Q
- Vesicles produced by Golgi that contain digestive enzymes with low pH, function in apoptosis, and break down nutrients, bacteria, and cell debris
A
Lysosomes
15
Q
- Transport of various substances in vesicles
- Plays an important role in modifying and packaging proteins
- Contains flattened sacs called cisternae
- Cis face: for incoming vesicles
- Trans face: for secretory vesicles
A
Golgi
16
Q
- Common in liver and kidney
- Breakdown substances, fatty acids, and amino acids
- In plant cells, modify by-products of photorespiration
- In germinating seeds: they are called glyoxysomes that break down stored fatty acids
- Produce or break down H2O2: used to oxidize substrates
A
Peroxisomes
17
Q
- Made of tubulin
- Serve to provide support and motility for cellular activities
- Act as spindle apparatus: guides chromosomes during division
- Can be found in flagella and cilia
- Found in a 9x2 array
A
Microtubules
18
Q
- Provide support for maintaining cell shape
A
Intermediate Filaments
19
Q
- Made of actin and involved in cell motility
- Found in skeletal muscle, amoeba, pseudopod, and cleavage furrows
A
Microfilament
20
Q
- Include centrosomes and basal bodies
- Found at the base of each flagellum and cilium and organize their development
- Found in a 9x3 array
- Plant cells lack centrioles and divide via cell plates, but they do have MTOCs
A
Microtubule Organizing Centers (MTOCs)
21
Q
- Moves materials between organelles and/or plasma membranes
A
Transport Vacuoles
22
Q
- Receptacles of nutrients which merge with lysosomes to breakdown food
A
Food Vacuoles
23
Q
- Exert turgor when filled to maintain rigidity, store nutrients, carry out functions performed by lysosomes in animal cells
- Have a specialized membrane called tonoplast
A
Central Vacuoles
24
Q
- Where plants store starch, pigments, and toxic substances
A
Storage Vacuoles
25
Q
- In single-celled Protista (amoeba and paramecium)
- Collect and pump excess water out of the cell via active transport
A
Contractile Vacuoles
26
Q
- Provide support in plants, fungi, protists, and bacteria
A
Cell Walls
27
Q
- In animals between adjacent cells
- Occupied by fibrous structural proteins, adhesion proteins, and polysaccharides secreted by cells
- Provide mechanical support and helps bind adjacent cells
- Collagen is most common protein to bind adjacent cells
- Network of collagen and proteoglycans connected to integrins in membrane via fibronectin and laminin
- Functions in transmitting signals between inside and outside of cell
- Cells adhere to EMC in two ways:
1. Focal adhesions: EMC connected to actin filaments in cell
2. Hemidesmosomes: EMC connected intermediate filaments - Fibroblasts: cells that produce collagen and connective tissue elements
A
Extracellular Matrix
28
Q
- In plant cells and include chloroplasts (photosynthesis site), leucoplasts (storage of starch), lipids (as elaioplasts), and proteins (as proteinoplasts), and chromoplasts: store carotenoids
A
Plastids
29
Q
- Double layered organelles that make ATP
- Serve as site of fatty acid catabolism/Beta-oxidation
- Have own DNA and ribosomes
A
Mitochondria
30
Q
- Microtubules (flagella and cilia), microfilaments, intermediate filaments, aids in cell division, cell crawling, and movement of cytoplasm and organelles
- Note on plant cells and water:
1. Hypotonic solution: Vacuole swells and becomes turgid. Fungal cells remain turgid due to wall, but animal cells burst
2. Isotonic solution: plant cell is flaccid
3. Hypertonic solution: cell is plasmolyzed (cytoplasm pulled away from cell wall)
A
Cytoskeleton
31
Q
- Network of organelles and structures, directly or indirectly connected, that function in transport of proteins and other macromolecules in or out
- Includes plasma membrane, ER, Golgi, nuclear envelope, lysosomes, vacuoles, vesicles, endosomes
A
Endomembrane System
