Chapter One Flashcards
What is the functional product of most genes?
A polypeptide, which is a linear sequence of amino acids that folds into units that
What is a trait?
Any characteristic that an organism displays.
What do Morphological traits affect?
The appearance of an organism.
What do physiological traits affect?
The ability of an organism to function.
What does the third category of traits?
Those that affect an organisms behavior
What is trans-acting factor?
A regulatory protein that binds to a regulatory element in the DNA and exerts a trans effect
How are the chemical properties of organic molecules essential for cell vitality?
The breaking of chemical bonds during the degradation of small molecules provides energy to drive cellular process; and their roles as building blocks for the synthesis of larger molecules.
What are the 4 important categories of larger collular molecules?
Nucleic acids (i.e. DNA and RNA)
Proteins
Carbohydrates
Lipids
What form Macromolecules?
Nucleic acids, proteins, and carbohydrates
What are macromolecules composed of?
Many repeating units of smaller building blocks
What is DNA?
The largest macromolecule found in living cells
A single DNA molecule can be composed of what?
A linear sequence of hundreds of millions of nucleotides
The formation of cellular structures relies on what?
The interaction of molecules and macromolecules
DNA is associated with what?
Many proteins that provide organization to the structure of chromosomes.
Within a eukaryotic cell, the chromosomes are contained where?
In a compartment called the cell nucleus.
In Eukaryotic cells, the nucleus is bounded by what?
A double membrane composed of lipids and proteins that shields the chromosomes from the rest of the cell.
The organization of chromosomes within a cell nucleus does what?
Protects the chromosomes from mechanical damage and provides a single compartment for genetic activities such as gene transcription
The formation of large cellular structures arises from what?
Interactions among different molecules and macromolecules, and in turn, are organized to make a complex living cell.
DNA is formed how? And is associated with what?
DNA is formed from the linkage of nucleotides, to produce a very long macromolecule. The DNA associates with proteins to form a chromosome
The chromosomes are located where?
Within a membrane-bound organelle called the nucleus, which along with other organelles is found ina complete cell.
Is DNA a small molecule, a macromolecule or an organelle?
Macromolecule
The characteristics of a cell depend on what?
The types of proteins that it makes.
What is the proteome?
All of the proteins that a cell makes at a given time.
What are some functions of proteins?
Help determine the shape and structure.
Insert into cell membranes and aid in the transport of ions and small molecules across the membrane.
Tubulin is what and does what?
A protein that assembles into large structures known as microtubules, which provide the cell with internal structures and organization.
What are enzymes?
A protein that functions to accelerate chemical reactions within a cell.
Some enzymes play a role in what? What are they called?
The breakdown of molecules or macromolecules into smaller units. They are catabolic enzymes and are important in the utilization of energy.
Anabolic enzymes and accessory protein function how?
In the synthesis of molecules and macromolecules throughout the cell.
What does DNA stand for?
Deoxyribonucleic Acid
The DNA does what?
Stores the information needed for the synthesis of all celllar proteins. It codes for the production of proteins in the correct cell at the proper time and in suitable amounts.
DNA’s ability to store information is based on what?
Its structure
DNA is composed of what?
A linear sequence of nucleotides
What are nucleotides?
The repeating structural unit of nucleic acids, composed of sugar, phosphate and a base.
Each nucleotide contains one of what four nitrogen-containing bases?
Adenine (A)
Thymine (T)
Guanine (G)
Cytosine (C)
DNA sequences within genes contain information to do what?
Direct the order of amino acids within polypeptides according to the genetic code.
In the genetic code, a three-base sequence specifies what?
One particular amino acid among 20 possible choices.
One or more polypeptides form what?
A functional protein.
What amino acid sequence correlates with this DNA sequence:
ATG GGC CTT AGC
Methionine
Glycine
Leucine
Serine
What amino acid sequence correlates with this DNA sequence:
TTT AAG CTT GCC
Phenylalanine
Lysine
Leucine
Alamine
DNA is found within what?
Large structures known as chromosomes
What are chromosomes?
The structures within living cells that contain the genetic material. Genes are physically located within the structure of chromosomes. Biochemically, chromosomes contain a very long segment of DNA, which is the genetic material, and proteins which are bound to the DNA and provide it with an organized structure.
An average sized human is expected to contain how many different genes?
1000
Which types of macromolecules are found in chromosomes?
DNA
Proteins
Small amounts of RNA when transcription is occurring.
What is gene expression?
The process of using a gene sequence to affect the characteristics of cells and organisms.
What is transcription?
The DNA sequence within a gene is copied into a nucleotide sequence of RNA
What does RNA stand for?
Ribonucleic Acid
What’s another name for Protien-Encoding genes?
Structural genes
What do protein-encoding genes do?
Carry the information for the amino acid sequence of a polypeptide
What is the 1st product when a protein-encoding gene is transcribed?
A RNA molecule known as a messenger RNA (mRNA)
The sequence of nucleotides within the mRNA determines what?
The sequence of amino acids in a polypeptide.
One or more polypeptides then forld to form and assemble what?
A functional protein
What is the central dogma of genetics?
The idea that the usual flow of genetic information is from DNA to RNA to polypeptide (protein).
In addition, DNA replication serves to copy the information so that it can be transmitted from cell to cell and from parent to offspring.
What is another name for central dogma of genetics?
Central dogma of molecular biology.
Where is the information to make a polypeptide stored?
In DNA
Which of the following is not a constituent of a cell’s proteome?
a. an enzyme
b. a cytoskeletal protein
c. a transport protein
d. an mRNA
d. an mRNA
A gene is a segment of DNA that has the information to produce a functional product. The functional product of most genes is
a. DNA
b. mRNA
c. a polypeptide
d. all of the above
c. a polypeptide
The function of the genetic code is to
a. promote transcription
b. specify the amino acids within a polypeptide
c. alter the sequence of DNA
d. none of the above.
b. specify the amino acids within a polypeptide
The process of transcription directly results in the synthesis of
a. DNA
b. RNA
c. a polypeptide
d. all of the above
b. RNA
In genetics, what trait is primarily focused on? WHy?
Morphological traits
They are easy to evaluate.
What are morphological traits again?
The traits that affect the appearance, form and structure of an organism.
What are physiological traits again?
The traits that affect the ability of an organism to function.
What is an example of a physiological trait?
The rate at which a bacterium metabolizes a sugar such as lactose.
How are physiological and morphological traits controlled?
By the expression of genes.
Behavioral traits are what again?
Traits that affect the ways an organism responds to its environment.
What is an example of behavioral traits?
The mating calls of bird species.
What are the four levels of biological organization?
Molecules
Cells
Organisms
Populations
Genes are expressed at the _________.
Molecular level. In other words, genes transcription and translation lead to the production of a particular protein, which is a molecular process.
Proteins often function at the ________.
Cellular level. The function of a protein within a cell affects the structure and workings of that cell.
An organism’s traits are determined by the characteristics of what?
Cells.
What is the organism level?
When the level of observation or experimentation involves a whole organism.
What is a species?
A group of organisms that maintain a distinctive set of attributes in nature.
The occurance of a trait within a species is an observation at the _______.
Population level.
What are alleles?
An alternative form of a specific gene.
What is genetic variation?
Genetic differences among members of the same species or among different species.
What underlies the genetic varioation that we see among individuals?
Changes in the nucleotide sequence of DNA
What are gene mutations?
A relativly small mutation that affects only a single gene.
Mutations result in what?
Genetic variation in which a gene is found in two or more alleles.
Often gene mutations alter what?
The expression or function of the protein that the gene encodes.
Alterations can also occur in what?
The structure of a chromosome.
Or the total number of chromosomes.
What is another critical factor that determines an organism’s traits?
Environment- the surroundings in which an organisms exists.
What is phenylketonuria?
A human genetic disorder arising from a defect in phenylalanine hydroxylase
What is diploid?
An organism or cell that contains two copies of each type of chromosome
The two copies of each chromosome are called what?
Homolog
What is homologs?
One of the chromosomes in a pair of homologous chromosomes.
What are somatic cells?
Any cell of the body except for germ-line cells tha give rise to gametes
What is a gamete?
A reproductive cell (usually haploid) that can unite with another reproductive cell to create a zygote. Sperm and egg cells are types of gamates.
Why are sperm and egg cells termed haploid?
They contain half the number of chromosomes
What are haploids?
The phenomenon that gametes contain half the genetic material found in somatic cells. For a species that is diploid, a haploid gamete contains a single set of chromosomes.
What can enhance genetic variation?
Sexual reproduction
What is biological evolution?
Also termed evolution.
The accumulation of genetic changes in a species or population over the course of many generations.
What is natural selection?
The process whereby differential fitness acts on the gene pool. When a mutation creates a new allele that is beneficial, the allele may become prevalent within future generations because the individuals possessing this allele are more likely to reproduce and pass the beneficial allele to their offspring.
Gene expression can be viewed at which of the following levels?
a. molecular and cellular levels
b. organism level
c. population level
d. all of the above.
D. all of the above.
Variation in the traits of organisms may be attributable to
a. gene mutations
b. alterations in chromosome structure
c. variation in chromosome number
d. all of the above.
d. all of the above.
A human skin cell has 46 chromosomes. A human sperm cell has
a. 23
b. 46
c. 92
d. none of the above.
a. 23
Evolutionary change caused by natural selection results in species with
a. greater complexity
b. less complexity
c. greater reproductive success in their native environment
d. the ability to survive longer.
c. greater reproductive success in their native environment
What is model organisms?
An organism studied by many scientists so that researchers can more easily compare their results and begin to unravel the properties of a given species.
What are common examples of model organisms?
Escherichia coli ( a bacterium) Saccharomyces cerevisiae (a yeast) Drosophila melanogaster (fruit fly) Caenorhabditis elegans (a nematode worm) Mus musculus (mouse) Arabidopsis thaliana (a flowering plant.)
What are the three areas of the study of genetics?
Transmission
Molecular
Population Genetics
What is the study of transmission genetics?
Examining the relationship between the transmission of genes from parent to offspring and the outcome of the offsprings traits.
Who provided the ground work for genetics?
Gregor Mendel
What is the fundamental approach of a transmission geneticist?
The genetic cross.
What is the genetic cross?
A mating between two individuals and the analysis of their offspring in an attempt to understand how traits are passed from parent to offspring.
What is the goal of molecular genetics?
To understand how the genetic material works at the molecular level.
Understand the molecular features of DNA and how these features underlie the expression of genes.
Molecular geneticists often study what?
Mutant genes that have abnormal function.
What is genetic approach?
In research, the study of mutant genes that have abnormal function. by studying mutant genes, researchers may better understand normal genes and normal biological processes.
What is loss-of-function mutation?
A change in a genetic sequence that creates a loss-of-function allele.
What is a loss-of-function allele?
An allele of a gene that encodes an RNA or protein that is nonfunctional or compromised in function.
Population geneticists hav developed what?
Mathematical theories to explain the prevalence of certain alleles within a population of individuals.
Population geneticists are particularly interested in what?
Genetic variation and how that variation is related to an organism’s environment.
What are the two types of scientific approach to genetics?
Hypothesis testing
Discovery-based science
What is another name for hypothesis testing?
Scientific Method
What is hypothesis testing?
Using statistical tests to deteremine if the data from experimentation are consistent with a hypothesis.
What is the scientific method?
A basis for conducting science. It is a process that scientists typically follow so they may reach verifiable conclusions about the world in which they live.
The scientific method provides a way to what?
Validate or invalidate a particular hypothesis.
What is discovery-based science?
Experimentation that does not require a preconceived hypothesis. In some cases, the goal is to collect date to be able to formulate a hypothesis.
What are the five components of the scientific method?
- background information is provided.
- most experiments involve hypothesis testing.
- figure follows the experimental steps the scientists took to test the hypothesis.
- the raw data are given
- an interpretation of the data is given.
Which of the following is not a model organism?
a. mus musculus (laboratory mouse)
b. escherichia coli (a bacterium)
c. saccharomyces cerevisiae (a yeast)
d. sciurus carolinensis (gray squirrel).
d. sciurus carolinensis (gray squirrel).
A person studying the rate of transcription of a particular gene is working in the field of
a. molecular genetics
b. transmission genetics.
c. population genetics
d. none of the above.
a. molecular genetics
The scientific method involved which of the following?
a. the collection of observations and the formulation of a hypothesis.
b. experimentation
c. data anaylsis and interpretation.
d. all of the above.
d. all of the above.
At the molecular level, what is a gene? Where are genes located?
A chromosome is a very long polymer of DNA. A gene is a specific sequence of DNA within that polymere; the sequence of bases creates a gene and distinguishes it from other genes. Genes are located in chromosomes, which are found within living cells.
Briefly explain how gene expression occurs at the molecular level.
A gene (a sequence of DNA) is first transcribed into RNA. The genetic code within the RNA is used to synthesize a protein with a particular amino acid sequence. The second process is called translation.
What is meant by the term genetic variation? Give two examples of genetic variation not discussed in chapter 1. What causes genetic variation at the molecular level?
Genetic variation involved the occurance of genetic differences within members of the same species or different species. Within any population, variation may occur in the genetic material. Variation may occur in particular genes so that some individuals carry one allele and other individuals carry a different allele. An example would be differences in coat color among mammals. Variation may also occur in chromosome structure and number. In plants, differences in chromosome number can affect disease resistance.
What is DNA sequence?
A sequence of nucleotides. Each nucleotide may have one of four different bases (A, T, G, or C). We focus on the sequence of bases.
Explain the relationship between a gene and trait.
A gene is a segment of DNA. For most genes, the expression of the gene results in the production of a functional protein. The functioning of proteins within a living cell affects the traits of an organism.
Explain the relationship between gene and chromosome
A gene is a segment of DNA that usually encodes the information for the production of a specific protein. Genes are found within chromosomes. Many genes are found within a single chromosome.
Explain the relationship between allele and gene.
An allele is an alternative version of a particular gene.
Explain the relationship between DNA sequence and amino acid sequence.
A DNA sequence is a sequence of nucleotides. The information within a DNA sequence specifies the amino acid sequence within a protein.
The technique known as DNA sequencing enables researchers to determine the DNA sequence of genes. Would this technique be used primarily by transmission geneticists, molecular geneticists or population geneticists?
Molecular geneticist.
Many organisms are studied by geneticists. Of the following species, do you think it would be more likely for them to be studied by a transmission geneticist, a molecular geneticists or a population genticist? A. Dogs b. E. Coli C. Fruit Flies d. Leopards E. corn
A. transmission geneticists B. Molecular genticists C. Both transmission and molecular geneticists. D. population geneticists. E. Transmission geneticists.
