The Cell Flashcards
cell (defn)
basic fundamental unit of all living things.
plasma membrane (cell membrane) (defn)
bounds the cell and encloses the nucleus and cytoplasm; phospholipid bilayer.
cytoplasm (defn)
consists of specialized bodies called organelles and cytosol; fluid matrix consisting of water and dissolved substances such as proteins and nutrients.
peripheral proteins (defn)
proteins that attach loosely to the inner or outer surfaces of the membrane.
integral proteins (defn)
proteins that extend to the interior of the phospholipid bilayer.
transmembrane proteins (defn)
proteins that span across the membrane and appear at both of the outer surfaces.
amphipathic (defn)
both hydrophilic and hydrophobic (ex. phospholipid bilayer)
fluid mosaic model (defn)
term describing characteristic of environment like the plasma membrane that has scattered proteins and cytosol that is a fluid matrix.
phospholipid bilayer/membrane (2)
- selectively permeable
- small, uncharged, polar molecules (ex. H2O, CO2) and nonpolar hydrophobic molecules (O2) can pass; large molecules (glucose) and charged species (Na+, Cl-, K+) cannot freely pass.
Types of molecules that can pass through the phospholipid bilayer are ____, ______, ______ molecules (ex. ___, ___ ) and ________, _____________ molecules (ex. __ ).
Types of molecules that cannot pass freely are ______ molecules (ex. ________ ) and _______ species (ex. ___, ___, ___)
small, polar, uncharged (H2O, CO2)
uncharged, hydrophobic (O2)
large (glucose)
charged (Na+, Cl-, K+)
Types of proteins (8)
- Channel proteins
- Ion channels
- Porins
- Carrier proteins
- Transport proteins
- Recognition proteins
- Adhesion proteins
- Receptor proteins
Channel protein
provides open passageway to hydrophilic molecules.
Ion channels
allow the passage of ions.
In muscle and nerve cells, ions are called gated channels and respond to certain stimuli to allow passage of specific ions (Na+, K+).
Gated channels
ion channels of the nerve and muscle cells that respond to certain stimuli to allow passage of specific ions (Na+, K+).
Porins
allow passage of certain ions and small polar molecules (ex. aquaporin).
Aquaporins
found in the plasma membrane of certain cells, specifically of the kidneys and plant roots, that dramatically increase the rate of H2O passage.
Carrier proteins
bind to specific molecules and go through conformational change then transfer molecule across the membrane (ex. glucose carrier protein).
Transport proteins
use energy (ATP) to transfer molecules across the membrane. The process is called “active” transport because it uses energy. (ex. Na+-K+ antiporter pump).
Recognition proteins
glycoproteins with short polysaccharide chains attached that give each cell a unique identification; provides distinction between cells (self cells vs. foreign cells).
Recognition proteins are ____proteins with short _____________ _______.
glycoproteins
polysaccharide chains
Adhesion proteins
attach cells to neighboring cells or provide anchors for internal filaments or tubules that give stability to the cell.
Receptor proteins
provide binding sites for hormones or trigger molecules
Cholesterol (also part of plasma membrane)
provides rigidity to plasma membrane of animal cells. In plants, sterols provide rigidity to plant’s plasma membrane.
Cholesterol provides rigidity to plasma membrane of _______ cells. Plant cells have _____ that provide rigidity to their plasma membrane.
animal
sterols
Glycocalx
on the surfaces of bacteria cell walls and some animal cell membranes; consists of glycolipids or glycoproteins; provide adhesive capabilities, barrier to infection, and markers for cell-to-cell recognition.
_______ are on the surfaces of bacteria cell walls and some animal membranes. They consist of _______ or ______ and have three functions (3).
Glycocalx glycoproteins or glycolipids 1. provide adhesive capabilities 2. barrier to infection 3. marker for cell-to-cell recognition.
Nucleus (4)
- bound by nuclear envelope consisting of two phospholipid bilayers
- contains DNA as chromatin, then chromosome during replication
- nucleosomes are coiled DNA with histones
- nucleoli is concentration of DNA in process of manufacturing ribosomes
Nucleosomes are ______ DNA with ______.
Nucleoli is _________ DNA in the process of manufacturing _________.
coiled; histones
concentrated; ribosomes.
Ribosomes
subunits that are assembled in the nucleoli and consist of RNA and proteins. They are 60S and 40S in the nucleus and become 80S in the cytoplasm. In the cytoplasm they assist in amino acid to protein translation.
Endoplasmic Reticulum
flattened sacs involved in production of various materials. Rough ER creates glycoproteins. Smooth ER creates lipids and hormones. The liver cell’s smooth ER breaks down toxins, drugs, and toxic byproducts from cellular respiration.
Rough endoplasmic reticulum create __________. Smooth endoplasmic reticulum create ________ and ______.
glycoproteins
lipids and hormones
Golgi Apparatus
flattened sacs that package lipids and proteins into vesicles
Lysosomes
vesicles from the Golgi Apparatus that contain digestive enzymes; break down food, cellular debris, and foreign invaders such as bacteria; low pH is maintained in lysosomes that is favorable for digestive enzymes.
Peroxisomes
break down hydrogen peroxide (H2O2 -> H2O + O2), fatty acids, amino acids. Common in liver and kidney cells. In plant cells peroxisomes modify byproducts of photorespiration and in germinating seeds, gloxysomes break down stored fatty acids to help generate energy for growth.
Peroxisomes break down ________ ________, ______ ______, and _______ ______ into water and oxygen. They are common in the ______ and ______ cells. In plant cells peroxisomes modify byproducts of ________. In germinating seeds, __________ break down stored fatty acids to help generate ______ for growth.
hydrogen peroxide, fatty acids, amino acids
liver and kidney
photorespiration
glyoxysomes; energy
