Chapter 4 Flashcards
Glass lenses magnify the image of the specimen in
Light microscopy
Electrons are passed through a thin specimen for viewing on a screen in
Transmission electron microscopy (TEM)
Electrons are reflected off the surface of the specimen for viewing on a screen in
Scanning electron microscopy (SEM)
The average size of a human cell is
30um
Human cells range from the smaller _______ to the largest ________
Red blood cell at 7-8 um, oocyte at 120um
Human cells can have a variety of shapes such as
Cube, round, columnar, cylinder, disc or irregular
The shape and size of a human cell determines its
function
The three main structural components of a cell are
Plasma (cell) membrane, nucleus, cytoplasm
Membrane bound organelles include:
Rough ER, smooth ER, mitochondria, Golgi apparatus, peroxisome and lysosome
Non-membrane bound organelles include:
Ribosomes, centrosome, proteasome and cytoskeleton
Cell organelles are permanent features while stored molecules named ______ vary in amount and presence
Inclusions
Three primary functions of any cell are:
Maintain integrity and shape, get nutrients for metabolism, dispose of wastes
The lipid components in a cell membrane include
Phospholipids, cholesterol and glycolipids
The cell membrane lipids that form a barrier between the cytoplasm and interstitial fluid are:
Phospholipids
The cell membrane lipids that strengthens and stabilizes the membrane is
Cholesterol
The cell membrane lipids that contribute to the glycocalyx are
Glycolipids
In a membrane’s bilayer, this region is hydrophobic (water-repelling).
fatty acid tails in the middle of the membrane
Cell membrane proteins that extend across the width of the membrane are _____ while those associated with only one of the cell membrane surfaces are ____
Integral, peripheral
The six major roles of membrane proteins are:
Transport, receptor, identity marker, enzyme, anchoring site, cell-adhesion
These membrane proteins have binding sites for chemical messengers (ligands).
receptors
These membrane proteins break down chemicals, such as chemical messengers that have finished stimulating the cell.
enzymes
These membrane proteins regulate movement of substances across the membrane, and include channels, carriers, and pumps
transport proteins
Ions and water can enter or leave the cell through this type of protein in the plasma membrane.
gated or leak channels
These transport proteins allow small molecules (such as water) and ions (such as sodium) to continually pass in and/or out of a cell.
leak channels
These transport proteins can open and close to control the movement of ions into and/or out of a cell.
gated channels
. These glycoproteins contribute to the glycocalyx and help the immune system recognize normal body cells.
Identity marker molecules
. These membrane proteins attach to similar proteins in neighboring cells, to hold cells together, and to extracellular molecules, allowing communication with other cells.
Cell-adhesion proteins
These membrane proteins or glycoproteins bind to specific chemicals which can signal the cell to perform a specific activity
receptor proteins
These membrane proteins attach to cytoskeletal proteins
Anchoring proteins
The movement of a substance from an area of high concentration to an area of low concentration, powered by the kinetic energy of the individual particles.
diffusion
What is the effect of all of the following on the diffusion rate?
1. higher temperature 2. lower molecular weight 3. steeper concentration gradient 4. greater surface area 5. higher permeability
increase diffusion rate
The movement of small, nonpolar molecules down a concentration gradient existing across a cell membrane is an example of
Simple diffusion
Oxygen, carbon dioxide, and steroids can enter or leave a cell through this part of the plasma membrane.
lipid bilayer
The movement of charged, polar molecules down a concentration gradient existing across a cell membrane requires a channel protein; this process is
Facilitated diffusion
The diffusion of water through a selectively permeable membrane; the result is a change in the volume of fluid on both sides of the membrane.
osmosis
This is a measure of the hydrostatic pressure required to stop osmosis.
osmotic pressure
Name the two processes that move a substance against its concentration gradient
Active transport and secondary active transport (coupled transport)
This process uses energy derived directly from ATP breakdown to move a substance against its concentration gradient
Active transport
This process uses energy derived from the movement of second substance moving down its concentration gradient to move a substance against its concentration gradient
Secondary active transport (coupled transport)
General term for vesicular transport mechanisms that bring large particles or objects into a cell.
endocytosis
Vesicular transport used to excrete substances from a cell.
exocytosis
Engulfment of large particles -even whole cells - by specialized cells such as white blood cells.
phagocytosis
Nonspecific intake of proteins by most cells is by this vesicular transport process.
pinocytosis
Selective intake of specific substance by vesicular transport
receptor-mediated endocytosis
Cell communication through direct contact often involves the
Glycocalyx
In general, ligands (signals) interact with one of these three cell receptor types
Channel (chemically) linked, enzymatic, G protein-coupled
Name the organelle that consists of sacs and tubules involved in synthesis of proteins (in the rough variety) and carbohydrates and lipids (in the smooth variety).
endoplasmic reticulum
Name the organelle responsible for packaging cell products for secretion.
Golgi complex
This structure, made by the Golgi apparatus, stores cell products and releases them via exocytosis.
secretory vesicle
Name the organelle that digests particles that a cell has endocytosed.
lysosome
Name the organelle responsible for breaking down amino acids and fatty acids; it is abundant in cells active in detoxification
peroxisome
Name the organelle responsible for manufacturing most ATP.
mitochondrion (mitochondria, plural)
These small organelles are the site of protein synthesis
ribosomes
Name the organelle responsible for breaking down proteins within a cells.
proteasome
Name the organelle that organizes the spindle fibers and is necessary for cell division
centriole
These cytoskeletal proteins push the chromosomes around during cell division.
spindle fibers
The only location for a _________ in humans is on the sperm; it propels the entire cell.
Flagellum
These hair-like extensions on the surfaces of some cells provide a way to move fluid over the surface of the cell.
cilia
These finger-like projections from a cell’s surface increase the absorptive ability of a cell by increasing its surface area. In some cases, they form a thick layer called the brush border.
microvilli
This type of cell-to-cell membrane junction prevents materials from moving between cells
Tight junction
This type of cell-to-cell membrane junction prevents cells from being pulled apart.
Desmosome
This type of cell-to-cell membrane junction allows adjacent cells to move materials directly from one cell to another
Gap junction
This type of membrane junction anchors the basal layer of certain types of cells to the underlying components
Hemidesmosome
The ______ ______ is a double membrane with pores; the outer membrane is continuous with the rough endoplasmic reticulum.
Nuclear envelope
. Name the organelle that contains the cell’s chromosomes
Nucleus
Name the region in the nucleus responsible for manufacturing ribosomal RNA.
nucleolus
The ______ ______ is a double membrane with pores; the outer membrane is continuous with the rough endoplasmic reticulum.
Nuclear envelope
Name the organelle that contains the cell’s chromosomes.
Nucleus
Name the region in the nucleus responsible for manufacturing ribosomal RNA
nucleolus
In a cell that is not dividing, the filamentous mass of DNA and DNA associated proteins are collectively named
Chromatin
The segment of DNA that functions as a discrete unit in DNA expression and codes for one polypeptide
Gene
Term for all the genes of one person
genome
The system that enables 4 nucleotides to distinguish the 20 different amino acids
genetic code
The structures required for transcription are
DNA, ribonucleotides, RNA polymerase
The manufacture of RNA from DNA, within the nucleus of a cell
transcription
DNA is unwound and hydrogen bonds broken in this part of transcription.
Initiation
RNA polymerase joins RNA nucleotides together after base pairing in this part of transcription.
Elongation
The mRNA is completed and DNA hydrogen bonds & rewinds in this part of transcription
Termination
The purines found in DNA and RNA
adenine, guanine
The pyrimidines found in RNA
cytosine, thymine
The base pairs, from the law of complementary base pairing
A-T and G-C
The sugar in RNA, instead of the deoxyribose in DNA
ribose
DNA or RNA: which is double-stranded?
DNA
The required structures for translation are
Ribosomes, mRNA, tRNA and amino acids
The manufacture of protein from RNA, in the cytoplasm of a cell
Translation
The type of RNA that is a mirror-image copy of the gene and controls the sequence of amino acids when a protein is made
messenger RNA (mRNA)
The type of RNA that is found in the protein-making organelles of a cell
ribosomal RNA (rRNA)
The type of RNA that delivers amino acids to the proteinmaking organelles in the cytoplasm
transfer RNA (tRNA)
The base sequence AUG is always found at the beginning end of mRNA is the
Start codon
One of these three sequences, UAA, UAG or UGA, is the ____ _____ that ends the translation of mRNA.
Stop codon
The sequence of 3 DNA nucleotides that specifies a single amino acid
base triplet
The sequence of 3 mRNA nucleotides that specifies a single amino acid
codon
The sequence of 3 tRNA nucleotides that specifies a single amino acid
anticodon
The three steps of translation are
Initiation, elongation and termination
The beginning of mRNA translation is _____ as the ribosome subunits and tRNA carrying methionine and the mRNA assemble.
Initiation
Charged tRNAs pair their anticodons with the codons on mRNA during the ____ phase of translation.
Elongation
A release factor binds at the stop codon of mRNA during the _____ phase of translation
Termination
DNA is considered the control center of the cell because
It directs the protein synthesis
This type of cell division results in two identical daughter cells.
Mitosis
This type of cell division results in 4 genetically dissimilar cells with half the chromosomes of the parent cell.
Meiosis
The first gap phase, the stage in a cell cycle right after division, in which the cell grows and functions
G1
The synthesis phase in a cell cycle, in which DNA replication occurs; this is the phase in which DNA is most susceptible to mutation
S
The term used for making new copies of a cell’s DNA in preparation for cell division
replication
This brief interval after the S phase includes replication of centrioles and preparation for division
G2
The term for the stage of a cell that is not preparing to divide; the cell is performing its specialized functions
G0
The mitotic stage in which chromosomes condense in preparation for cell division; each chromosome consists of 2 sister chromatids connected by a centromere
prophase
The mitotic stage in which the chromosomes are arranged at the equator of the cell
metaphase
The mitotic stage in which the chromosomes move to opposite poles
anaphase
The mitotic stage in which the chromosomes uncoil; cytokinesis usually occurs at the same time
telophase
This process evenly divides the cytoplasm and organelles between two daughter cells.
Cytokinesis
This process describes the self-induced death of a cell, or cell suicide.
Apoptosis
What do “ICF” and “ECF” stand for?
intracellular fluid, extracellular fluid
