Chapter 1 - Life Begins with Cells Pt.2

Cells

________ 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.