Chapter 1 Flashcards
the massive amount of information contained in our_____—the deoxyribonucleic acid (DNA) found within all of our chromosomes
genome
The completed sequence, published in_____, has an accu- racy greater than 99.99%; fewer than one mistake was made in every 10,000 base pairs (bp)!
2003
The results of human genome projects have shed considerable light on basic questions,
such as (5)
how many genes we have
how genes direct the activi- ties of living cells
how species evolve
how single cells develop into complex tissues
and how defective genes cause disease
controversial example of a genetic technology is________. In 1997, Ian Wilmut and his colleagues produced clones of_____, using mammary cells from an adult animal
mammalian cloning
Sheeps
In____, the first pet was cloned, a cat named CC (for “carbon copy” or “copy cat”)
2002
The adult human body is composed of______ of cells
trillions
Most human cells contain the following:
•____ human chromosomes, found in___ pairs
• ___ meters of DNA
• Approximately_______ genes coding for proteins that perform most life functions
• Approximately_____ DNA base pairs per set of chromosomes, containing the bases A, T, G, and C
46, 23
2
22,000
3 billion
The human genome is a complete set of
human chromosomes
People have____ sets of chromosomes, one set from each parent.
two
each set of chromosomes is composed of a______ that is approximately _____nucleotide base
pairs long.
DNA sequence
3 billion
Estimates suggest that each set of chromosomes contains about ________________ genes.
22,000 protein-encoding
Humans also have a small amount of DNA in their_______, which has also been sequenced.
mitochondria
_________ provide the means of modify- ing the traits of animals and plants in ways that would have been unimaginable just a few decades ago.
genetic technologies
Certain species of jellyfish emit a “green glow” produced by a gene that encodes a bioluminescent protein called___________. When exposed to blue or ultraviolet (Uv) light, the protein emits a striking green-colored light.
green fluorescent protein (GFP)
stands as the unifying discipline in biology by allow- ing us to understand how life can exist at all levels of complex- ity, ranging from the molecular to the population level.
Genetics
is the root of the natural diversity that we observe among members of the same species and among different species.
Genetic variation
is centered on the study of genes.
Genetics
is classi- cally defined as a unit of heredity, but such a vague definition does not do justice to the exciting characteristics of genes as intricate molecular units that manifest themselves as critical contributors to cell structure and function.
gene
At the molecular level, a___ is a segment of DNA that has the information to produce a functional product.
gene
The functional product of most genes is a_______—a linear sequence of amino acids that folds into units that constitute proteins.
polypeptide
Genes are commonly described according to the way they affect______, which are the characteristics of an organism.
traits
In humans, for example, we observe traits such as
eye color, hair texture, and height
the breaking of _______ during the degradation of small molecules provides energy to drive cellular processes.
chemical bonds
four important categories of larger cellular molecules are
nucleic acids (i.e., DnA and rnA)
proteins
carbohydrates
lipids
three of these—(3)—form macromolecules that
are composed of many repeating units of smaller building blocks.
nucleic acids
proteins
carbohydrates
is the largest macromolecule found in living cells
DnA
A single DnA molecule can be composed of a linear sequence of hundreds of millions of building blocks called______!
nucleotides
are small organic molecules and they are linked to each other and form the building
blocks of DnA, which is a macromolecule.
nucleotides
is a component of chromosomes, which also contain
proteins that contribute to chromosome structure.
DnA
within a________, the chromosomes are contained in a compartment called the cell nucleus. the nucleus is bounded by a double membrane composed of lipids and proteins
that shields the chromosomes from the rest of the cell.
eukaryotic cell
—a membrane-bound compartment with a specialized function.
organelle
the ______protects the chromosomes from mechanical damage and provides a single compartment for genetic activities such as gene transcription.
cell nucleus
protects the chromosomes from mechanical damage and provides a single compartment for genetic activities such as gene transcription.
cell nucleus
(3)are organized to make a complete living cell
cellular molecules, macromolecules, and organelles
the entire collection of proteins that a cell makes at a given time is called its
proteome
are the “workhorses” of all living cells.
proteins
the protein known as___ can assemble into large structures known as microtubules, which provide the cell with internal structure and organization.
tubulin
are inserted into cell membranes and aid in the transport of ions and small molecules across the membrane
Proteins
Proteins may also function as biological motors. An interesting case is the protein known as______, which is involved in the contractile properties of muscle cells.
myosin
, which accelerate chemical reactions, are a particularly important category of proteins.
Enzymes
The___ stores the information needed for the synthesis of all proteins.
DNA
DNA is composed of a linear sequence of_______, each of which contains one of four nitrogen-containing bases:
nucleotides
adenine (A), thymine (T), guanine (G), or cytosine (C).
In the code, a three-base sequence, called a____, specifies one particular amino acid among the 20 possible choices.
Codon
The process of using a gene sequence to affect the characteristics of cells and organisms is referred to as
gene expression.
In the first step, known as ________, the DNA sequence within a gene is copied into a nucleotide sequence of ribonucleic acid (RNA).
transcription