Topic 3: cellular level of organization Flashcards
what is the cell?
-basic structural and functional unit of the body
-can perform all basic life functions
what are the names of the outermost part of the cell?
-cell membrane
-plasma mebrane
-plasmalemma
what is the cell membrane composed of?
-phospholipid bilayer
-cholesterol
-membrane proteins
-membrane carbohydrates
-microvilli
what does the phospholipid bilayer divide?
-the intracellular fluid and the extracellular fluid
what is intracellular fluid?
-fluid inside the cell
what is extracellular fluid
-fluid outside the cell
what are the two types of membrane proteins?
-integral proteins
-peripheral proteins
what are integral proteins?
-integrated within the membrane
-they have a hydrophobic region to interact with the fatty acid tails
-those that extend across the entire membrane are called transmembrane proteins
what are peripheral proteins?
-attached to the surface of the membrane
-also can be attached to the surface of an integral protein
what are the functions of membrane proteins?
-enzymes
-transporters (ATP)
-channels (NO ATP)
-receptors (HORMONES)
-anchors
-identity markers (for the immune system)
what are membrane carbohydrates?
-only on the outer surface
-bound to other proteins (glycoproteins) or lipids (glycolipids)
-used for cell recognition (sperm recognizing an egg)
-anchor cells together
what is cholesterols purpose in the membrane?
-they are scattered throughout the membrane
-add stability + fluidity
-doesn’t break apart at extreme temps
what is the phospholipid bilayer composed of?
-phosphate head group (hydrophilic)
-fatty acid tails (hydrophobic)
-double layered
-heads on the outer side, tails on the inner
what are microvilli?
-small projections of the cell membrane
-used to increase surface area (increased absorption)
they are best seem on small intestine cells and kidney cells
what is the fluid mosaic model?
-shows the phospholipid bilayer
-shows membrane proteins
-fluid - components can move (phospholipids + some proteins)
-mosaic - proteins dot the surface
what is the cytoplasm?
- an AREA (not a fluid)
-area between the inside of the cell membrane and the outside of the nucleus
what are the two divisions of the cytoplasm?
-cytosol
-organelles
what is cytosol?
-a gel-like fluid
-contains water, ions (K+, Na+), suspensions of carbohydrates, proteins, and lipids
-can have inclusions (melanin or glycogen)
what are organelles?
-structures that perform specific functions
-essential for life
-can be non-membranous (direct contact with cytosol)
-can be membranous (isolated from cytosol)
what are non-membranous organelles?
-ribosomes
-centrosome
-cytoskeleton
what are ribosomes?
-sites for protein synthesis
-contain rRNA (ribosomal RNA) and proteins
-can be free in cytosol
-can be attached to endoplasmic reticulum
where are proteins destined depending on the location of ribosomes?
-free (destined for cytosol, mitochondria, or nucleus)
-ER (destined for all other sites)
what are the two components of centrosomes?
-a pair of centrioles (perpendicular)
-the pericentriolar matrix
what are the functions of centrosomes
-organizing centers for microtubules
-spindle apparatus for cell division
-organizes the cytoskeleton
what is the cytoskeleton?
-3 types of cytoskelton
-they all support cell shape (structural)
-formed from proteins
-important in cell movement, cell division, movement/anchoring of organelles + proteins (receptors + enzymes)
what are the 3 types of cytoskeleton?
-microfilaments
-intermediate filaments
-microtubules
what are microfilaments made of? what are their functions?
-made of actin
-muscle contraction (done with help of myosin)
-cell locomotion
-cytokinesis
what are intermediate filaments made of? what is their function?
-composition is tissue specific (ex: keratin)
-supports the cytoplasm
-structural support for cell attachment and tissue development (scaffolding for the cell)
what are microtubules made of? what is their function?
-hollow tubes made of tubulin
-form centrioles, spindle apparatus, cilia, and flagella
-structural
-move or secure organelles in place
what are membranous organelles?
-mitochondria
-endoplasmic reticulum
-golgi apparatus/complex
-lysosomes
-nucleus
what is the mitochondria?
-site of ATP synthesis
-contains its own DNA, RNA, and proteins
-has a double membrane
what is the endoplasmic reticulum?
-membranous network throughout the cytoplasm
-two types
-rough ER
-smooth ER
what is the rough ER?
-has ribosomes attached
-site of the synthesis of secretory, lysosomal, and membrane proteins
what is the smooth ER?
-lacks attached ribosomes
-continuous with the rough ER
-synthesizes lipids and steroid hormones
what is the golgi complex?
-stacks of mebrane discs
-modifies proteins (trims or adds carbs and lipids)
-sorts, packages, and delivers proteins
-delivers to the cell membrane, lysosomes, or for secretion
what are lysosomes?
-filled with digestive enzymes
-digest bacteria, viruses, worn out organelles
-clean up function
what is the nucleus?
-the largest membranous organelle
-cell control center
-cells can have more than one
what are the different parts of the nucleus?
-nuclear envelope
-nucleolus
-chromosomes/chromatids
what is the nuclear envelope?
-a double membrane with nuclear pores
-cytoplasm connection
-connected to ER
what is the nucleolus
-non-membranous
-dense region of DNA, RNA, + proteins (less light)
-where ribosomes are made and assembled
what are chromosomes?chromatids?
-contains DNA + histone proteins
-can either be dispersed (chromatin)
-can be condensed + individually visible
what is chromatin?
-uncoiled DNA
-not individually visible
-in this form most of the time (when the cell is not dividing)
where are condensed chromosomes found?
-in dividing cells
what are the 3 principle parts of the cell?
-nucleus
-cytoplasm
-plasma membrane
