Midterm 1: Eukaryotic Cells Flashcards
What is the cell membrane composed of (the fluid arrangement)?
Fluid Mosaic Model- Phospholipids, cholesterol, carbohydrates, and proteins (PCCP)
Controls what enters and exits the cell.
Selective Permeable
What easily enters the cell membrane WITHOUT help?
Fat-soluble, small, uncharged molecules
What needs facilitated diffusion/help to move across the cell membrane?
Large, uncharged, water-soluble molecules and charged molecules
What type of molecule is cholesterol?
Amphipathic (both hydrophobic and hydrophillic)
Name the two functions of cholesterol in the cell membrane.
Reduce cell membrane: fluidity and permeability
Name two different types of proteins:
Integral (intrinsic) and Peripheral (extrinsic)
What are integral proteins?
have at least one HYDROPHOBIC region that anchors them to the hydrophobic core of the lipid bilayer
What are Peripheral proteins?
Associate with one surface of the cell membrane, attached to integral proteins OR the hydrophillic head
What are Transmembrane proteins?
Integral proteins that span the entire width of the membrane
Name the 6 functions of the cell membrane.
JETRAT: Junctions Enzymes Transport Recognition Anchorage Transduction
Where are carbohydrates located?
attached to proteins (glycoproteins) and fats (glycolipids)
What are the 3 functions of carbohydrates?
Cushioning and protections for the cell membrane
JR: Junction and Recognition
What is the Nucleus?
Storage facility for genetic information (DNA)
Describe the process of DNA synthesis.
DNA–> mRNA (transcription)
mRNA–> protein (translation)
Where does transcription occur?
nucleus
Where does translation occur?
Ribosomes
Describe the two layers of the nucleus’s lipid bilayer.
inner lipid bilayer: nuclear lamina
outer lipid bilayer: continuous with the ER
What is the role of nuclear lamina?
inner lipid bilayer of the nucleus that is lined with protein and organizes DNA
What are the holes perforating the nuclear envelope called?
Nuclear pores–lined with protein
What is the role of nuclear pores?
they are lined with proteins that control what enter and exit the nucleus
What is the semimatrix fluid that is found inside the nucleus called?
nucleoplasm
What is found within nucleoplasm?
Chromatin and the Nucleolus
What is chromatin?
DNA and protein
What occurs within the nucleolus?
protein synthesis and rRNA synthesis
Where is cytoplasm located?
between the cell membrane and the nucleus
What 3 things are contained within the cytoplasm?
cytosol, cytoskeleton, and organelles
What occurs in cytosol?
metabolic pathways: Glycolosis, glucogenesis, pentose phosphate pathway (PPP), and fatty acid synthesis
What is contained within cytoskeleton?
fibrous proteins: actin, microtubles, and intermediate filaments
What is the role of cytosol?
aqueous gel-like component of the cytoplasm where organelles (ions, small molecules, and macromolecules) are suspended
What is the role of cytoskeleton?
Structure and support inside the cell:
- anchors the cell
- aids in cell motility
- helps materials inside the cell move
What are ribosomes composed of?
proteins and rRNA
Where are ribosomes synthesized?
nucleolus
What is the site of protein synthesis? (translation)
ribosomes
Where are they found?
free (in cytosol) or bound (attached to ROUGH ER)
What is the ER made of?
Lipid bilayer membrane–tubules and cisternae (flattened sacs) [lumen/cisternal space within tubules and sacs are fluid filled]
What is the Smooth ER responsible for?
LIPID processing
converts fat soluble toxins into h2o soluble substances
sequesters Ca2+ from cytosol
What is the Rough ER responsible for?
PROTEIN processing
transports proteins to Golgi bodies
What are Golgi apparatus made of?
cisternae; membrane is lipid bilayer
What is the Golgi’s job?
modify proteins received by the rough ER
What is the difference between Cis and Trans of Golgi?
Cis- receiving side
Trans- shipping side
Mitochondria are composed of what 3 things?
circular DNA
double membrane
mitochondrial matrix
What is the double membrane?
inner lipid bilayer–contains cristae (the deep folds)
outer lipid bilayer–define’s organelles surface
What is the mitochondrial matrix?
fluid-filled space in the inner membrane
What is circular DNA?
can synthesize rRNA, tRNA, mRNA
What metabolic activities occur in mitochondria?
Krebs cycle/ETC
Fatty acid oxidation
What other role does mitochondria play?
apoptosis- programmed cell death
What are lysosomes?
surrounded by a lipid membrane
site of intracellular digestion
Approx. PH of lysosomes?
5
What reactions are peroxisomes involved in?
fatty acid oxidation
neutralize free radicals
myelin synthesis
cholesterol synthesis
What is the extracellular matrix (ECM)?
3D network of macromolecules– OUTSIDE the cell
What is the most significant enzyme in the ECM?
matrix metalloproteinases
What are the 2 classes of macromolecules in the ECM?
fibrous proteins
glycosaminoglycans (GAGs)
Name the components of fibrous proteins?
structural (collagen and elastin)
adhesive (fibronectin and laminin)
What are glycosaminoglycans (GAGs)?
unbranched polysaccharide chain composed of repeating disaccharide units–> most are linked to a specific core protein, forming proteogycans
What fills the space of the EMC in the form of a hydrated gel?
GAGs
What happens to the components of macromolecules?
they are synthesized intracellulary and then transported extracellulary via Exocytosis
What are the 4 functions of the ECM?
Cell structure and support
Anchor the cell in place
cell binding–forming tissues
regulates cellular functions (adhesion, growth, migration, differentiation)
What are Proteins?
Large, complex molecules that do MOST of the work within the cell
