Chapter 3 Flashcards
The cell theory: three steps
1) a cell is the basic unit of life
2) all living things are composed of cells
3) all cells come from preexisting cells
How are cells classified
Cells are classified according to their internal organization
What are composite cells created for
They are created for the purposes of studying only
A typical cell is what
Composite cell - a cellular model that exhibits the most important characteristic
The three main structures of a cell and a description
1) nucleus - this is the control center or central processing station for the cell
2) cytoplasm - cytosol (intercellular fluid) -> has organelles
3) plasma membrane - this is inside the extra cellular
What does a nucleus contain
- contains genetic info of a cell, and controls all activity
- DNA contains the master code for making RNA and proteins/enzymes
- therefore, the DNA dictates the function of the cell
What is the structural function of a nucleus
- double layered nuclear membrane
- nuclear pores
- chromosomes/chromatin
- nucleolus -> contains RNA
What is a nucleolus
A nucleolus synthesizes RNA, which in turn combines with protein to create ribosomes, which can also synthesize proteins
Define cytoplasm
A gel-lik substance of cells that contain many tiny suspended structures
Define cytosol
“Little organs,” membranous, non-membranous
Define and explain ribosomes
They are called protein factories and are the site that the protein synthesis will happen at. The ribosomes in turn create many “enzymes” which are structural and functional proteins.
Where are ribosomes:
Free and bound
- Ribosomes are free floating in cytoplasm, attached to the outer surface of the endoplasmic reticulum.
Free ribosome - synthesizes proteins for the cells immediate use
Bound ribosome - synthesizes proteins to be transported immediately to organelles or exported from the cell.
Endoplasmic reticulum is considered what in the human body
the endoplasmic reticulum is considered the “manufacturing center” in the human body
Explain the difference between rough and smooth endoplasmic reticulum (ER)
Rough: has ribosomes, and manufactures proteins
Smooth: no ribosomes, manufactures lipids, then prepares these proteins and lipids for the Golgi apparatus
What is the Golgi apparatus and what does it do?
The Golgi apparatus is considered the “Processing and packaging plant” in the human body.
- refines synthesized products
- is the packaging and shipping center
- is packed into vesicles and shipped to different cell locations or cell membranes to export
What are vesicles and what are the four types
A vesicle is a membrane-bound storage and shipping containers.
1) secretory -> contain products to be exported from the cell
2) endocytic -> contains substances that are exported externally
3) peroxisomes -> contain enzymes that detoxify wastes produced by the cell
4) lysosomes -> contain digestive enzymes
Define cytoskeleton and its organelles
Cytoskeleton - internal scaffolding, that helps maintain the cells shape. The basic cytoskeleton organelles are; cell fibers, centrosome, molecular motors, cell extensions
Define cell fibers
Cell fibers are the cytoskeleton which also support and anchors the other cellular structures in the body.
Define microtubules
Microtubules are tiny hollow tubes of protein
Define microfilaments
Microfilaments are thin solid fibers of protein
Microtubules and microfilaments do what for the cell
They for the basic framework to provide support for the cell
What is a centrosome and what is its important role
A centrosome is the “microtubule - organizing center” and is a non-membranous structure in the cell.
A centrosome is important in the role of cell division
Define pericentriolar material
Pericentriolar material is a cloud like mass of material surrounding centrioles, active to help new growth of new microtubules
What is the description of mitochondria
- “Powerhouse of the cell”
The primary purpose is the synthesis of ATP - cellular respiration and utilizes O2 and produces CO2
- the number of mitochondria varies based on the energy requirements of the cell
- surrounded by a double membrane, and inner one is highly folded