3 - Cellular Level of Organization Flashcards
List the 5 principle parts of the cell
Cell Membrane Cytoplasm Non-membranous organelles Membranous organelles Nucleus
Define plasmlemma
Cell Membrane
What are the parts of a cell membrane
Phospholipid bilayer Cholesterol Membrane proteins Membrane carbohydrates Microvilli
Define the phospholipid bilayer and its function
PPPPP FFFFF FFFFF PPPPP (phospholipids on the outsides, fatty acids on the inside) Keeps the ICF and the ECF seperated
What is the function of cholesterol in the cell membrane
To add stability
What are the two types of membrane proteins?
Integral Proteins
Peripheral Proteins
What are the two types of integral proteins
transmembrane - spans the whole bilayer
within the membrane - spans the length of one phospholipid
What is a peripheral protein?
One that attaches to the outside of the membrane or the outside of a integral protein.
What are some membrane protein functions?
- enzymes
- transporters
- channels
- receptors
- anchors
- identity markers (for immune system)
Define membrane carbohydrates and their functions
found only on outside of the cell membrane, attached to either a protein (glycoprotein) or lipids (glycolipid).
• Functions:
i. cell recognition (e.g. egg and sperm)
ii. anchor cells together
Define microvilli and its function
• small projections of cell membrane
• Function:
increase surface area
• best seen on cells of the small intestine and kidney
Define the Fluid Mosaic Model
fluid - membrane constituents can move around (phospholipids and some proteins)
mosaic – proteins dot surface like tiles in a mosaic
Define cytoplasm and its parts
AREA between the inside of the cell membrane and the outside of the nucleus.
Parts:
Cytosol
Organelles
Define cytosol
gel-like intracellular fluid
contains water, ions (e.g. K+, Na+) and a suspension of carbohydrates, proteins, and lipids
may contain inclusions e.g. melanin (pigment), glycogen (stored glucose)
What are the two classifications of organelles
Membranous - not in contact with cytosol
Non-membranous - in full contact with cytosol
Which organelles are non-membranous?
Ribosomes
Centrosomes
Cytoskeleton
Which organelles are membranous?
All but Ribosomes, Centrosomes, Cytoskeleton
What are ribosomes?
sites for protein synthesis
contain ribosomal RNA (rRNA) + proteins
What do cytosolic ribosomes make?
proteins destined for cytosol, mitochondria, nucleus
What do ER ribosomes make?
All proteins not made by cytosolic ribosomes.
What are centrosomes and their function?
dense area of cytoplasm, usually contains 2 centrioles (function uncertain - some cells lack them)
organizes microtubules to form spindle apparatus (for cell division)
organizes cytoskeleton
What is the cytoskeleton and it’s function?
determines cell shape (cell support)
formed from proteins
functions:
important in cell movement (ex flagellum), cell division, movement/anchoring of organelles + proteins (e.g. receptors, enzymes)
What are the three types of cytoskeleton?
Microfilaments
intermediate filaments
microtubules
Define microfilaments and their function
made of actin Function: • muscle contraction (with myosin) • cell locomotion • maintenance of cell shape and projections (e.g. microvilli) • cytokinesis
Define intermediate filaments and their function
composition is tissue specific e.g. keratin
Function:
• support the cytoplasm (scaffolding for the cell)
Define microtubules and their function
hollow tubes made of tubulin Function: • form: a) centrioles b) spindle apparatus c) cilia (short) d) flagella (long) • structural • move or secure organelles in place
Describe a mitochondion
site of ATP synthesis
contains own DNA, RNA, + proteins
have a double membrane
Describe the endoplasmic reticulum
membranous network throughout cytoplasm 2 types: i. Rough ER (RER) ribosomes attached ii. Smooth ER (SER) lacks attached ribosomes continuous with RER
What does the RER synthesize?
- synthesis of secretory, lysosomal and membrane proteins
What does the SER synthesize?
- synthesis of lipids and steroid hormones
What is the Golgi Apparatus?
stacks of membrane discs
modifies (e.g. trims or adds CHO groups), sorts, packages, and delivers proteins/lipids to cell membrane, lysosomes, or for secretion (cellular post office)
Describe lysosomes
filled with digestive enzymes
digest bacteria, viruses, worn-out organelles (clean up function)
How many nuclei per cell?
0-many
0 for rbc, 1 for most, many for developing cells
What are the parts of the nucleus?
Nuclear envelope
Nucleolus
Chromosomes/Chromatids
Describe the nuclear envelope
double membrane with nuclear pores (two bilayer membranes, 4 phospholipids)
connected to ER
Describe the nucleolus
non-membranous
dense (less light gets through) region of DNA, RNA, + proteins where ribosomes are made and assembled
Describe chromosomes/chromatids and their various states
contain DNA + histone proteins
can be:
i. dispersed = Chromatin
DNA uncoiled + not individually visible
in this form MOST of the time (when cell is not dividing
It’s a big mess of yarn so that you can read individual strings
ii. condensed + individually visible
found in dividing cells (during mitosis/meiosis)
