Chapter 1 - Life Begins with Cells Pt.2

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.

G1

The M and S phases are separated by two gap stages, the** ________ phase and G2 phase,** during which mRNAs and proteins are made.

ATP

To create the low pH environment, proteins located in the** lysosomal membrane** pump hydrogen ions into the** lysosome** using energy supplied from ________.

Cells

________ can produce a particular** mRNA** only when the encoded protein is needed, thus minimizing wasted energy.

unique functions

The ________ and micro- climates of the various cell compartments are due largely to the proteins that reside in their membranes or interior.

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**

Teton Mountains

The ________ in Wyoming, now about 14, 000 feet high and still growing, didn't exist a mere 10 million years ago.

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**

asexual process

Mitosis** is a(n) ________ since the daughter cells carry the exact same genetic information as the parental cell.

complex macromolecules

Directly or indirectly, all of our food is created by plant cells using sunlight to build ________ during** photosynthesis**

cytoplasm of fat

The circulating insulin signal causes glucose transporters in the ________ and muscle cells to move to the cell surface, where they begin importing glucose.

E coli cells

________ prefer glucose as a sugar source, but they can survive on lactose in a pinch.

Elaborate systems

________ regulate the assembly and disassembly of the cytoskeleton, thereby controlling cell shape.

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.

Mobile elements

________, which were discovered first in plants, are responsible for leaf color variegation and the diverse beautiful color patterns of Indian corn kernels.

ribosomes

Proteins are secreted from the cell and most membrane proteins are made on ________ associated with the endoplasmic reticulum (ER)

abundant protein

Collagen**, the single most ________ in the animal kingdom, is a major component of the extracellular matrix in most tissues.

fundamental defect

The ________ in cancer is the loss of the ability to control the growth and division of cells.

membrane proteins

The attachment of some ________ to other molecules inside or outside the cell restricts their lateral movement.

eukaryotic cells

Most of the DNA in ________ is located in the nucleus, extensively folded into the familiar structures we know as** chromosomes**

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.

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.

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.

cell surface

The binding of many other** hormones** and of growth factors to receptors on the ________ triggers different signal- transduction pathways that also lead to changes in the transcription of specific genes.

genome of an organism

The ________ comprises its entire complement of DNA.

hormone insulin

The rise in blood glucose is sensed by cells in the pancreas, which respond by releasing their stored supply of the** protein ________**

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.

eukaryotic cell cycle

The ________ commonly is represented as four stages.

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.

ribosomes

Some proteins are made on ________ that are free in the** cytosol**

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.

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.