1.2 Eukaryotic Cells**** Flashcards
1
Q
eukaryotic cells vs prokaryotic cells
A
Eukaryotic Cells:
• unicellular or multicellular
• contain a true nucleus enclosed in a membrane
Prokaryotic Cells:
• unicellular
• no nucleus, no membrane-bound organelles
2
Q
Figure 1.1 Eukaryotic Cell
A
- cell membrane
- cytoplasm
- nuclear membrane
- nucleus
- nucleolus
- endoplasmic reticulum (rough and smooth)
- ribosomes
- mitochondria
- Golgi apparatus
- lysosome
- centrioles
- endocytic vesicles
insert image of figure 1.1 on page 5
3
Q
hand draw a eukaryotic cell with constituting organelles and structures
A
take a picture of the drawing and insert here
- cell membrane
- cytoplasm
- nuclear membrane
- nucleus
- nucleolus
- endoplasmic reticulum (rough and smooth)
- ribosomes
- mitochondria
- Golgi apparatus
- lysosome
- centrioles
- endocytic vesicles
4
Q
organelles
A
- most eukaryotic organelles are membrane-bound → compartmentalization of functions
5
Q
cytoplasm vs cytosol
A
6
Q
mitosis
A
eukaryotic reproduction which forms 2 identical daughter cells
7
Q
nucleus
A
- control center of the cell
- contains all of the genetic material necessary for cellular replication
- location of DNA → compartmentalized transcription
8
Q
nuclear membrane/envelope
A
double membrane which maintains a separate and distinct nuclear environment from the cytoplasm
9
Q
nuclear pores
A
allows for selective two-way exchange of material between the nucleus and cytoplasm
10
Q
nucleolus
A
- subsection of nucleus where ribosomal RNA (rRNA) is synthesized
- 25% of the volume of the nucleus
11
Q
genes
A
coding regions of DNA
12
Q
histones
A
organizing proteins around which linear DNA is wound
13
Q
chromosomes
A
linear strands of DNA
14
Q
mitochondria
A
- powerplants of the cell → metabolic functions
- can induce apoptosis via release of enzymes from electron transport chain
15
Q
apoptosis
A
programmed cell death
16
Q
mitochondrial structure
A
- Outer membrane: barrier between cytosol and inner environment
- Inner membrane: contains cristae with molecules and enzymes necessary for electron transport chain
17
Q
cristae
A
highly convoluted structures with numerous infoldings which increase the SA available for electron transport
18
Q
mitochondrial matrix
A
- the space inside the inner membrane
- protons are pumped from the mitochondrial matrix to the intermembrane space establishes the proton-motive force
- These protons flow through ATP synthase to generate ATP during oxidative phosphorylation
- protons are pumped from the mitochondrial matrix to the intermembrane space establishes the proton-motive force
19
Q
intermembrane space
A
the space between the outer and inner membranes
20
Q
Figure 1.2 Mitochondrial Structure
A
insert image from page 7
21
Q
mitochondria cont…
A
- semi-autonomous → contain own genes and replicate independently of the nucleus via binary fission
- example of cytoplasmic (extranuclear) inheritance
- thought to have evolved from anaerobic prokaryote engulfing an aerobic prokaryote and establishing a symbiotic relationship
- example of cytoplasmic (extranuclear) inheritance
22
Q
cytoplasmic (extranuclear) inheritance
A
transmission of genetic material independent of the nucleus
23
Q
serial endosymbiosis theory
A
- organelles formed by one prokaryote engulfing another and the establishment of a symbiotic relationship between the two
- tries to explain the formation of some membrane-bound organelles
- in addition to mitochondria → chloroplasts and organelles of motility (flagella)
- tries to explain the formation of some membrane-bound organelles
24
Q
lysosomes
A
- membrane-bound structures which contain hydrolytic enzymes
- capable of breaking down different substrates such as substances ingested by endocytosis and cellular waste products
- *the lysosomal membrane sequesters these enzymes from self-damage to the cell
- however, can induce autolysis (apoptosis)
25
autolysis
lysosomal release of hydrolytic enzymes which degrade celllar components and cause cell death
26
endoplasmic reticulum (ER)
* a series of interconnected double membranes which are contiguous with the nuclear envelope
* the membrane folds into a complex structure of numerous invaginations with a central lumen
* transfers cellular materials to the Golgi apparatus via vesicles
* 2 types: RER and SER
27
rough endoplasmic reticulum (RER)
contains ribosomes → translation of proteins which are secreted into the lumen of the RER
28
smooth endoplasmic reticulum (SER)
* lipid synthesis (i.e. phospholipids for cell membrane)
* detoxification of drugs and poisons
* transports proteins from the RER into the Golgi apparatus
\*lacks ribosomes
29
Golgi apparatus
* made up of stacked membrane-bound sacs
* functions:
* receives vesicles containing cellular materials from the ER
* modify and sort cellular materials
* addition of various groups (carbohydrates, phosphates, and sulfates)
* introduce signal sequences with instructions for delivery
* repackage materials into vesicles for delivery to specific cellular locations (lysosomes, plasma membrane, or secretion)
* if product is destined for secretion → _exocytosis:_ secretory vesicle merges with cell membrane and is released
30
Figure 1.3 Relationship between lysosomes, ER, Golgi apparatus, cell memebrane and secretion (exocytosis)
insert image from page 8
31
Key Concept
insert image of key concept from page 8
\*not all cells have the same relative distribution of organelles → determined by function
32
peroxisomes
* membrane-bound organelle containing hydrogen peroxide
* breakdown very long fatty acid chains via ß-oxidation
* synthesis of phospholipids
* contain enzymes involved in the pentose phosphate pathway
33
the cytoskeleton
* maintains the cell's structure and shape
* provides a conduit for the transport of materials around the cell
* comprised of:
* microfilaments
* microtubules
* intermediate filaments
34
Figure 1.4 Components of the Cytoskeleton
insert figure 1.4
35
microfilaments
* made of solid polymerized rods of actin
* resistant to compression and fracture
* uses ATP and mysosin to generate force for movement (muscle contraction)
* during cytokinesis → microfilaments form the cleavage furrow → actin contracts and ring (cleavage furrow) pinches off
36
microtubules
* made of hollow polymers of tubulin proteins
* provide primary pathways for motor proteins kinesin and dynein to carry vesicles
37
microtubules continued…
* microtubules make up motile structures such as cilia and flagella
* cilia and flagella share the same structure:
* **9 + 2 structure:** 9 pairs of microtubules forming an outer ring and 2 microtubules in the center
* only seen in eukaryotic organelles of motility (bacteria have different structures)
38
Figure 1.5 Cilia and Flagella 9 + 2 Structure
insert image
39
microtubules continued….
* microtubules make up centrioles (found at the centrosome of a cell)
* 9 triplets of microtubules with a hollow center
* during mitosis → centrioles migrate to opposite poles → organize the mitotic spindle → microtubules project from centrioles → attach to kinetochores → pull apart sister chromatids
40
intermediate filaments
* made of diverse group of filamentous proteins (keratin, desmin, vimentins, and lamins)
* specific to type of cell and tissue type
* involved in cell-cell adhesion and overall integrity of cytoskeleton
* help anchor other organelles (nucleus)
* able to withstand a lot of tension → rigid
41
4 tissue types
* ***_epithelial_***
* ***_connective_***
* muscle
* nervous
42
epithelial tissue
* cover the body and line its cavities
* protect against pathogen invasion and desiccation
* absorption, secretion and sensation
43
basement membrane
underlying layer of connective tissue which keeps epithelial cells tightly joined to each other
44
parenchyma
* epithelial cells typically make up the parenchyma
* _the functional part of an organ_
* example: nephrons in kidneys, hepatocytes in liver, and parietal cells in stomach
\*epithelial cells are highly diverse and serve numerous functions depending on which organ they are found i n
45
epithelial cells continued….
* epithelial cells are often polarized:
* one side faces a lumen (hollow inside of an organ or tube) or the outside world
* other side interacts with underlying blood vessels and structural cells
* ex: small intestine → one side absorbs nutrients in the lumen and the other is involved in releasing those nutrients into circulation
46
connective tissue
* supports the body
* provides a framework for epithelial cells to carry out their functions
example: bones, cartilage, tendons, ligaments, adipose tissues and blood
47
stroma
* the supportive structure of a biological cell, tissue, or organ
* in contrast, the parenchyma is the functional aspect of a tissue
\*connective tissues are the main contributors to the stroma
48
extracellular matrix
* large network of proteins and other molecules that surround, support, and give structure to cells and tissues in the body
\*most cells in connective tissues produce and secrete materials such as collagen and elastin to from the extracellular matrix
49
1.2 Concept Check (#1)
insert image
**nucleus**: stores genetic information and is the site of transcription
**mitochondria**: involved in ATP synthesis and apoptosis
**lysosomes**: break down molecules ingested via endocytosis and cellular waste products; also induce autolysis (apoptosis)
**rough endoplasmic reticulum**: synthesizes proteins for secretion
**smooth endoplasmic reticulum**: lipid synthesis (i.e. phospholipids for cell membrane), detoxification of drugs and poisons, transports proteins from the RER into the Golgi apparatus
**Golgi apparatus**: packages, modifies and transports cellular products
**peroxisomes**: breakdown very long fatty acid chains via ß-oxidation, synthesis of phospholipids, contain enzymes involved in the pentose phosphate pathway
50
1.2 Concept Check (#2)
if someone had an enzyme deficiency which prevents the production of hydrogen peroxide → peroxisomes would not be able to break down very long fatty acid chains → fatty acids would accumulate in peroxisomes → oversized peroxisomes would displace other cellular contents → cell death
51
1.2 Concept Check (#3)
**microfilaments:** actin
**microtubules:** tubulin
**intermediate filaments:** vary by cell type (keratin, desmin, vimentin, lamins)
52
1.2 Concept Check (#4)
* flagella structure: 9 + 2 structure**:** 9 doublets of microtubules forming an outer ring and 2 microtubules in the center
* only seen in eukaryotic organelles of motility (bacteria have different structures)
* microtubule structure: 9 triplets of microtubules with a hollow center
53
1.2 Concept Check (#5)
* fibroblasts: connective tissue
* endothelial cells: epithelial cells
* α-cells: epithelial cells
* osteoblasts: connective tissue
* chondroblasts: connective tissue
