3 - Cellular Level of Organization Flashcards by mikayla kozarchuk

List the 5 principle parts of the cell

Cell Membrane
Cytoplasm
Non-membranous organelles
Membranous organelles
Nucleus

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Define plasmlemma

Cell Membrane

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What are the parts of a cell membrane

Phospholipid bilayer
Cholesterol
Membrane proteins
Membrane carbohydrates
Microvilli

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Define the phospholipid bilayer and its function

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PPPPP
(phospholipids on the outsides, fatty acids on the inside) 
Keeps the ICF and the ECF seperated

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What is the function of cholesterol in the cell membrane

To add stability

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What are the two types of membrane proteins?

Integral Proteins

Peripheral Proteins

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What are the two types of integral proteins

transmembrane - spans the whole bilayer

within the membrane - spans the length of one phospholipid

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What is a peripheral protein?

One that attaches to the outside of the membrane or the outside of a integral protein.

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What are some membrane protein functions?

enzymes
transporters
channels
receptors
anchors
identity markers (for immune system)

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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

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Define microvilli and its function

• small projections of cell membrane
• Function:
 increase surface area
• best seen on cells of the small intestine and kidney

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Define the Fluid Mosaic Model

 fluid - membrane constituents can move around (phospholipids and some proteins)
 mosaic – proteins dot surface like tiles in a mosaic

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Define cytoplasm and its parts

 AREA between the inside of the cell membrane and the outside of the nucleus.
Parts:
Cytosol
Organelles

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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)

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What are the two classifications of organelles

Membranous - not in contact with cytosol

Non-membranous - in full contact with cytosol

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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)