BIO7: Eukaryotic Cells: Organelles and the Cell Cyle Flashcards
What domain are eukaryotic cells?
Eukarya
What domain are prokaryotic cells?
Bacteria or archaea
What are differences between eukaryotic and prokaryotic cells?
Eukaryotic cells have membrane-bound organelles, DNA in nucleus, DNA wrapped in chromatin, can divide by sexual (meiosis) and asexual (mitosis) division, animal cells don’t have cell wall, flagella is made of 9+2 microtubules
What are the differences between prokaryotic cells and eukaryotic cells?
Prokaryotic cells don’t have membrane-bound organelles, no nucleus, no histone proteins/naked DNA, division by binary fission, bacterial cell walls of peptidoglycan, and flagella is made of flagellin protein
Domain eukarya
Protists,fungi, plantae, animalia
Protozoa
Single-celled eukaryotes that feed on organic matter such as other microorganisms or organic tissue/debris
Heterotroph
Organism that cannot manufacture its own food by carbon fixation/derives its intake of nutrition from other organic carbon
Endosymbiotic theory
Describes the evolution of eukaryotic cells that originally engulfed another prokaryotic cell and lived in symbiosis to become organelles
Epithelial tissue include what type of cells
Squamous cells, cuboidal cells, columnar cells that lines body cavities
Connective tissue includes what types of cells
Bone, tendons, ligaments, cartilage, adipose tissue, and blood
What is function fo the nucleus?
Contains and protects genetic material
What processes occur in the nucleus?
- DNA replication
- RNA processing
- transcription
What is the function of mitochondria?
Site of ATP production through the TCA cycle and oxidative phosphorylation that creates a H+ gradient harnessed by ATP synthase
What is the structure of mitochondria?
Inner and outer membrane with intermembrane space
Where is the cristae located?
Inner membrane of the mitochondria
Mitochondrial matrix
Space within the inner membrane that houses different enzymes of metabolism as well as mitochondrial DNA
How do mitochondria replace themselves?
They are self-replicating and contain all the machinery required for self-replciation
mtDNA
Mitochondrial DNA are small circular DNA that codes for proteins in the TCA cycle and oxidative phosphorylation which are passed down from maternal cytoplasm
What are unique about mitochondrial ribosomes?
They are different from ribosomes in the rest of the cell (70S) and are evident of the endosymbiotic theory
Lysosome
Organelles that house the enzymes required to break down polymers
What polymers do lysosomes affect?
Lipids, proteins, DNA, carbohydrates
Acid hydrolases
Enzymes that degreade molecules by hydrolysis
Autophagy
Self-degredation of damaged/defunct cell parts
What is the pH of lysosome?
~4.5
What is the pH of the cytoplasm?
~7.2
Endoplasmic reticulum
Continuous membrane-enclosed system composed of cisternae (flattened sacs)
What is the difference between rough and smooth ER?
Rough ER has ribosomes, smooth ER lacks ribosomes
What is the function of SER?
- Makes lipids
- Metabolizes carbohydrates, steroids, and toxins (liver)
- Stores and secretes Ca2+ in the SER of muscle cells
Myocytes
muscle cells
Sarcoplasmic reticulum
SER of mucle cells
Where are SER abundant?
Liver
What is the function of RER?
Translation and post-translational protein modification
What is the result of proteins made in the RER?
- Secreted by the cell
- Become part of the plasma membrane
- Be used in the ER, golgi, or lysosomes
Golgi apparatus
Modifies via post-translational modification, sorts, packages, and sends out proteins and lipids
What is the structure of the golgi apparatus?
Stacks of cisternae with cis and trans regions
Cisternae
Flattened discs in the ER and golgi
Cis region
Receives proteins from RER (packaged in vesicles)
Trans region
Where proteins and other molecules are sent from the golgi to their destination
How are proteins processed through the ER?
- Translation in the cytoplasm
- N-terminus signal sequence is translated
- Sequence recognized by BRP causes translation to pause the ribosomes to become docked on the RER
- Protein translated into the lumen of the RER
- Chaerone protein or other enzymes may modify it and signal peptide removed
- RER works with golgi to send proteins to the proper location
What is the function of peroxisomes?
- Breakdown of long chain fatty acids into shorter fatty acid chains
- Metabolize drgus/other toxins
- Carry out redox reactions producting H2O2
How do peroxisomes break down fatty acid chains?
Beta oxidation
What is the product of beta oxidation?
Produces acetyl-CoA (short chain)
Catalase
Breaks down damaging H2O2 in the peroxisome
Eukaryotic cell cycle
Interphase and mitotic phase
What processes are included in interphase?
G1 –> S –> G2
What processes are included in the mitotic phase?
Mitosis and cytokinesis
What is the function of interphase?
- Cell growth
- Prepares for cell division
- DNA replication
G0 phase
Cell is not replicating or dividing which may be a temporary or permanent state (neurons)
G1 phase
Cell growth
S phase
DNA replication
G2 phase
More cell growth
Prophase
- Chomatin condenses into chromosomes
- Nucleolus disappears
- Mitotic spindle is assembled
- Centrioles prepare to send out spindle fibers
Metaphase
Condensed and duplicated chromosomes line up along the metaphase plate
Anaphase
- Spindle fibers linked to the centromere of the chromosomes shorten
- Sister chromatids separate
- Cell elongates for division
Telophase
- Nuclear envelope reforms
2. Chromosomes de-condense
Cytokenesis
Division of the cytoplasm and organelles through the clevage furrow
What separates cells during cytokenesis?
Actin and myosin filaments contract to pinch cells apart throughout anaphase/telophase
Kinetochore protein complex
Where the centromere links to the spindle fibers
How is the cell cycle controlled?
Checkpoints at the G1, G2, and M phases that checks for certain conditions before proceeding
Apoptosis
Programmed cell death
Necrosis
Premature and un-programmed cell death due to cell injury
How is apoptosis triggered?
Extrinsic or intrinsic signal (e.g. cell stress, cell damage)
P53
Tumor suppressor gene that intrinsicly triggers apoptosis
Caspases
Class of protease enzymes
Protease
Enzymes that break down proteins and peptides