Studied by 10 peopleCells
________ can produce a particular mRNA only when the encoded protein is needed, thus minimizing wasted energy.
Mitosis
________ is an asexual process since the daughter cells carry the exact same genetic information as the parental cell.
Biological reproduction
________, with continuing evolutionary selection for a highly functional body plan, is why todays horseshoe crabs look much as they did 300 million years ago.
E coli cells
________ prefer glucose as a sugar source, but they can survive on lactose in a pinch.
eukaryotic cells
Most of the DNA in ________ is located in the nucleus, extensively folded into the familiar structures we know as chromosomes.
micro climates
The unique functions and ________ of the various cell compartments are due largely to the proteins that reside in their membranes or interior.
endoplasmic reticulum
Proteins are secreted from the cell and most membrane proteins are made on ribosomes associated with the ________ (ER)
ionic composition
The cytosol and the internal spaces of organelles differ from each other and from the cell exterior in terms of acidity, ________, and protein contents.
plasma membrane
The cytoskeleton prevents the ________ of animal cells from relaxing into a sphere it also functions in cell locomotion and the intracellular transport of vesicles, chromosomes, and macromolecules.
Teton Mountains
The ________ in Wyoming, now about 14,000 feet high and still growing, didn't exist a mere 10 million years ago.
normal human
With the exception of eggs and sperm, every ________ cell has 46 chromosomes.
Elaborate systems
________ regulate the assembly and disassembly of the cytoskeleton, thereby controlling cell shape.
Mobile elements
________, which were discovered first in plants, are responsible for leaf color variegation and the diverse beautiful color patterns of Indian corn kernels.
DNA
The chromosomes and the ________ they carry are copied during the S (synthesis) phase.
Gene expression
________, the overall process of selectively reading and using genetic information, is commonly controlled at the level of transcription, the first step in the production of proteins.
mutation rate
Chloroplasts, the organelles that carry out photosynthesis in plants, also have their own circular genomes. ________ may be good, bad, or indifferent.
M
The ________ and S phases are separated by two gap stages, the G1 phase and G2 phase, during which mRNAs and proteins are made.
insulin
The circulating ________ signal causes glucose transporters in the cytoplasm of fat and muscle cells to move to the cell surface, where they begin importing glucose.
ribosomes
Some proteins are made on ________ that are free in the cytosol.
fundamental defect
The ________ in cancer is the loss of the ability to control the growth and division of cells.
mechanical movements
The signals employed by cells include simple small chemicals, gases, proteins, light, and ________.
membrane proteins
The attachment of some ________ to other molecules inside or outside the cell restricts their lateral movement.
lipid molecules
The ________ and some proteins can float sidewise in the plane of the membrane, giving membranes a fluid character.
prokaryotic cells
In ________, most or all of the genetic information resides in a single circular DNA molecule about a millimeter in length; this molecule lies, folded back on itself many times, in the central region of the cell.
phospholipid layers
The two ________ of a membrane are oriented with all the hydrophilic ends directed toward the inner and outer surfaces and the hydrophobic ends buried within the interior.
Plants
________ have a less distinct division between somatic and germ- line cells since many plant cells can function in both capacities.
tough matrix
A specialized, especially ________, the basal lamina, forms a supporting layer underlying sheet- like cell layers and helps prevent the cells from ripping apart.
large molecular machines
In animal and plant cells, most ATP is produced by ________ located in two organelles, mitochondria, and chloroplasts.
sexual reproduction
In ________, the fusion of two cells produces a third cell that contains genetic information from each parental cell.
bacterial cells
Like ________, unicellular eukaryotes may be subjected to widely varying environmental conditions that require extensive changes in cellular structures and function.
Lysosomes
________ are assisted in the cells cleanup work by peroxisomes, these small organelles are specialized for breaking down the lipid components of membranes and rendering various toxins harmless.
extracellular matrix
In animals, the ________ cushions and lubricates cells.
mRNA
Producing a(n) ________ is the first and only in a chain of regulated events that together determine whether an active protein product is produced from a particular gene.
genome of an organism
The ________ comprises its entire complement of DNA.
circular DNA
This is the ________ present in mitochondria, the organelles in eukaryotic cells that synthesize ATP using the energy released by the breakdown of nutrients.
DNA polymerase
________, which is responsible for linking nucleotides into a DNA strand.
molecular parasites
Once viewed only as ________, mobile DNA elements are now thought to have contributed significantly to the evolution of higher organisms.
eukaryotic cell cycle
The ________ commonly is represented as four stages.
Hormone
________ binding changes the shape of the receptor so that it can bind to specific enhancer sequences in the DNA, thus turning the receptor into a transcriptional activator.
steroid hormones
Since ________ can circulate in the bloodstream, they can affect the properties of many or all cells in a temporally coordinated manner.
Cells
________ need to break down worn- out or obsolete parts into small molecules that can be discarded or recycled.
M
The replicated chromosomes separate during the ________ (mitotic) phase, with each daughter cell getting a copy of each chromosome during cell division.
Mobile elements
________ were later found in bacteria which they often carry and, unfortunately, disseminate genes for antibiotic resistance.
plasma membrane
The ________ and other cellular membranes are composed primarily of two layers of phospholipid molecules.
bacterial cells
Most eukaryotic cells take longer than ________ to grow and divide.
Cells
________ possess numerous receptor proteins for detecting signals and elaborate pathways for transmitting them within the ________ to evoke a response.
Cells
________ can move at rates on the order of 20 m /second.
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