Chp 2 Flashcards
A human cell consists of three major parts:
- plasma membrane
- Cytoplasm
- Nucleus
What are the two major roles of the plasma membrane
- it separates the internal cellular components from the external environment
- It regulates the movements of substances into and out of the cell
Describes the structure of the plasma membrane
- fluid mosaic model
The major chemical components are _______ and __________
- lipids and protein
The membrane lipids include:
- phospholipids
- Cholesterol
- Glycolipids
Define phospholipids
form a lipid bilayer that is the basic framework of the plasma membrane
Define cholesterol
molecules which strengthen the membrane
Define glycolipids
- perform functions on the membranes outer surface
The membrane proteins include:
- integral proteins, and peripheral proteins
Define integral proteins
- primarily transmembrane proteins (many of these are glycoproteins) and lipid linked proteins
Define peripheral proteins
- located on the inner and outer surfaces of the phospholipid bilayer: the carbohydrate portions of the glycolipids and glycoproteins form a cell surface coat called the glycocalyx
Some proteins form _________ through which specific substances may pass into or out of the cell
ion channels
Some proteins are _________ (carrier proteins) that carry specific substances across the membrane
- transporters
Some proteins are _________ for extracellular signalling molecules called _________
- receptors, ligands
Some glycoproteins and glycolipids are _________ involved in recognition of other cells
- cell identity markers
Some proteins serve as ________ which anchor membrane proteins of neighboring cells to eachother or to filaments inside and outside the cell
- linkers
Due to its chemistry and structure, the plasma membrane has ___________ that selectively regulates the passage of specific substances into and out of the cell
- selective permeability
The various fluids that substances move to or form include:
- intracellular fluid (ICF) or cytosol
- Extracellular fluid (ECF)
Extracellular fluid includes
- interstitial fluid located between cells of tissues
- Plasma located in lymphatic vessels
- Lymph located in lymphatic vessel’s
Specific substances move across the plasma membrane by:
- passive processes, active processes, or vesicular transport
In passive processes substances move across plasma membrane due to their own kinetic energy _______ a concentration gradient.
Down
_______ is a process in which substances move down a concentration gradient without any aid provided by membrane components
Diffusion
________ is the process in which water molecules diffuse down their concentration gradient through membrane channels between neighboring phospholipids
Osmosis
___________ is a process in which substances move down a concentration gradient with the aid of a membrane due to energy
Facilitated diffusion
In __________ substances move across a plasma membrane due to energy provided by ATP, ___________ a concentration gradient
Active processes, atp
In _______ transport, energy is expended so that vesicles either detach from the plasma membrane to import substances into the cell or fuse with plasma membrane to export substances from the cell
Vesicular
_______ is a process in which extracellular molecules and particles are surrounded, enclosed, and brought into the cell by an invaginating segment of the plasma membrane
Endocytosis
Three basic types of endocytosis are
Receptor-mediated endocytosis (involving a membrane receptor), phagocytosis(cellular eating), bulk phase endocytosis or pinocytosis (cellular drinking)
________ is a process in which intracellular vesicle enclosed substances are released into the extracellular fluid by membrane fusion with the plasma membrane
Exocytosis
______ is a process in which substances are moved by vesicles into a cell on one side, across the cell, and then out of the cell on the other side
Transcytosis
The _____ is the intracellular fluid in which organelles are suspended and in which solutes are dissolved; collectively all of these intracellular components form the cytoplasms
Cytosol
What provides shape to the cell and play roles in cell movements as well as movements of organelles within cells
Filaments
_______ are thin filaments that preform these functions, they also provide mechanical support, within fingerlike projections of the plasma membrane called ________
Microfilaments, microvilli
_____ are long thin cylindrical structures that participate in determining cell shape and function in the intracellular transport of organelles
Microtubules
_____ have a diameter between that of microfilaments and microtubules, they help position organelles as well as to strengthen and give shape to the cell
Intermediate filaments
Cilia form the…
Inner lining of the respiratory tract
_____ are typically short and numerous; are found in several types of human cells where their function is to move materials past the surfaces of these cells
Cilia
______ are typo long and few in number; only example in human cell is the tail of the sperm where its function is to propel the cell
Flagella
Microvilli are found where
In the small intestine, on the surface of egg cells, as well as on white blood cells
_____ float in the cytosol whereas _____ membrane bound ribosome are attached primarily to the endoplasmic reticulum
Free ribosomes, membrane bound ribosomes
Ribosomes are organelles where ____ occurs
Protein synthesis
Membranes that are studded with ribosomes that synthesize proteins destined to be secreted or delivered to lysosomes or to the plasma membrane
Rough er
Membranes have ribosomes but are sites for lipid synthesis, toxin detoxification, calcium storage in muscle cells
Smooth er
What provides protein and lipids from the rough we
Golgi complex
Suicide sacks
Lysosomes
Spherical membranes enclosed sacs that form from the golgi complex
Lysosomes
Small, spherical, membrane enclosed sacs that contain enzymes that use molecular oxygen to oxidize various organic molecules, important to the liver and kidney
Peroxisomes
Power house of the cell
Mitochondria
Provide energy for cellular processes
Mitochondria
Contains chromatin
Nucleus
Somatic cell progress through a cell cycle that consists of
Interphase and mitotic phase
The mitotic phase consisted of two major events :
Mitosis and cytokinesis
Process that divides the cytoplasms into two masses resulting in the formation of two daughter cells, each with its own set of identical genetic material
Cytokinesis
Cytokinesis begins toward the end of mitosis and involves the formation of a ______ typically at the equator of the cell
Cleavage furrow
Cells that undergo orderly, genetically programmed death
Apoptosis
A pathological type of cell death that results from tissue injury
Necrosis
