PCB3063 Ch 1 Overview of Genetics
An organism's genome consists of ______.
the DNA found in all of its chromosomes
The branch of biology that deals with heredity and variation is
genetics
Which of the following are correct descriptions of a gene?
- A segment of DNA that produces a functional product
- A unit of heredity
- A segment of DNA that influences one or more traits of an organism
The functional product of most genes is a(n)
protein, polypeptide, polypeptides, proteins, or RNA
The term that describes all of the DNA found in all of an organism's chromosomes is
genome
Genes are often described according to the way they affect the characteristics of an organism, which are called
traits
Genetics is the branch of biology that deals with ______.
heredity and variation
Which of the following molecules are nucleic acids?
- DNA
- RNA
A gene can be described as a unit of heredity or as a segment of _____
that produces a functional product.
DNA
The building blocks of DNA are called
nucleotides, nucleotide, or deoxyribonculeotides
A gene is a segment of DNA that produces a functional product, which is usually a(n) ____ , or as a unit of heredity that affects an organism's ____.
- polypeptide or protein
- traits, characteristics, or phenotype
Genes are the source of products for cellular function. The product of most genes is a ______.
polypeptide
Of the macromolecules found in living cells, the largest one is
DNA
A trait is a ______.
characteristic of an organism
In a eukaryotic cell, the ____ is surrounded by a double membrane that protects the chromosomes from the rest of the cellular components.
nucleus, nuclei, or DNA
Both DNA and RNA are ______ acids.
nucleic
DNA is made of ______.
nucleotides
In a eukaryotic cell, what are the advantages of having the chromosomes organized within a cell nucleus?
- It protects the chromosomes from damage.
- It provides a single compartment for activities such as gene transcription.
What is the largest macromolecule found in living cells?
DNA
Reason:
A protein has hundreds or thousands of amino acids compared to a single DNA molecule with hundreds of millions of nucleotides.
Which of the following are potential functions of proteins?
- Transport ions across the cell membrane
- Aid in cell structure and stability
- Accelerate chemical reactions
Where are the chromosomes located in a eukaryotic cell?
In the nucleus
An enzyme is a protein that ______.
accelerates a chemical reaction
An enzyme that breaks molecules into smaller components is called a(n) ____ enzyme, and an enzyme that synthesizes macromolecules is called a(n) ____ enzyme.
- catabolic
- anabolic
The abbreviation for deoxyribonucleic acid is
DNA
Organizing chromosomes within a cell nucleus protects chromosomes from mechanical damage and provides a single ____ for genetic activities such as transcription.
compartment or location
What is the genetic material of all living organisms composed of?
DNA
Which cellular molecules can accelerate chemical reactions, transport substances across the membrane, and provide structure and stability for a cell?
Proteins
A protein that can accelerate a chemical reaction is called a(n)
enzyme, enzymes, or catalyst
What is the main function of a cell's genetic material?
to code the production of proteins in the correct cell, at the proper time, and in suitable amounts
What are some of the functions of enzymes in cells?
- They breakdown molecules and macromolecules into smaller units.
- They synthesize molecules and macromolecules.
A DNA molecule is a linear sequence of subunits called
nucelotides
Adenine, thymine, guanine and cytosine are nitrogen-containing bases found in ______.
each nucleotide of DNA
True or false: All living organisms have genetic material composed of DNA.
True
Reason:
The genetic material of all living organisms is made of DNA. Viruses, some of which have RNA genomes, are not living entities.
The information in a(n) ____ molecule is stored in the sequence of its nucleotide bases.
DNA, RNA, DNA/RNA, or DNA or RNA
The primary function of DNA is to code for the production of
proteins, polypeptides, protein, polypeptide, or RNA
Most genes contain the information to direct the synthesis of a polypeptide. The order of amino acids in the polypeptide is specified according to the ____ code.
genetic
What are the subunits of DNA?
Nucleotides
In the genetic code, there are 64 codons consisting of ____ nucleotide(s) each that specify the 20 different amino acids. (Your answer will be a number).
3
What are the four nitrogen-containing bases found in the nucleotides that make up DNA?
Guanine
Adenine
Thymine
Cytosine
In living cells, DNA is found in large structures called ____, which are contained in the nucleus of a eukaryotic cell.
chromosomes
In a DNA molecule, information is contained in the sequence of ______.
nitrogenous bases
Which cellular molecules can accelerate chemical reactions, transport substances across the membrane, and provide structure and stability for a cell?
Proteins
The genetic code directs the order of ______ within a polypeptide based on the sequence of nucleotides within a DNA molecule.
amino acids
What is a karyotype?
A micrograph of all of the chromosomes in a cell
In the genetic code, how many nucleotides are necessary to specify one amino acid?
3
The DNA of human chromosomes is ______.
long
double-stranded
linear
What structures in a cell contain DNA?
Chromosomes
True or false: An average human chromosome contains approximately two million genes.
False
A micrograph of the chromosomes in a cell is called a(n)
karyotype
What is gene expression?
The use of a gene sequence to affect the characteristics of a cell or organism.
When a structural gene is expressed, its DNA sequence is ____ into RNA, which is then ___ to produce a polypeptide.
- transcripted
- translated
During transcription, the DNA sequence of a gene is copied into a sequence of ______.
RNA
Approximately how many genes are found on a typical human chromosome?
1000 different genes
The process of using a gene sequence to affect the characteristics of cells and organisms is called gene ______.
expression
Place the molecules produced when a gene is expressed in the correct sequence beginning with the gene.
1. DNA
2. mRNA
3. Protein
RNA is an abbreviation for ______.
ribonucleic acid
The process by which a DNA sequence is copied into an RNA sequence is called
transcription
A structural gene is a gene that encodes a(n)
protein, polypeptide, proteins, or polypeptides
What type of RNA contains the information required to synthesize a protein?
Messenger RNA
What is translation?
The synthesis of a polypeptide based on the sequence of mRNA
What does the central dogma of genetics describe?
The pathway of gene expression from DNA to RNA to protein
During transcription, the DNA sequence of a gene is copied into a sequence of ______.
RNA
Match each trait with the correct example.
What is a structural gene?
A gene that contains the information to synthesize a protein
A trait that affects the appearance, form, and structure of an organism is called a(n) ____ trait. A trait that affects the ability of an organism to function is called a(n) ____ trait. A trait that affects the way an organism responds to its environment is called a(n) ____ trait.
- morphological
- physiological
- behavioral
When a protein-encoding gene is transcribed, the RNA molecule that is produced is referred to as ___ RNA (mRNA).
messenger
Genes affect traits at several levels of biological organization. Match each level of organization with the correct description of gene function.
The synthesis of a polypeptide based on the nucleotide sequence of a messenger RNA molecule is called
translation
What is a species?
A group of organisms that maintains a distinctive set of attributes
The pathway of gene expression from DNA to RNA to protein is referred to as the ____ ____ genetics.
central dogma
Alternative versions of the same gene are called
alleles
The color of a butterfly is an example of a(n) ______ trait.
morphological trait
Match each type of trait with the correct description.
Different alleles of the same gene have different ___ sequences.
DNA, nucleotide, or nucleotides
Transcription and translation lead to gene expression at the ______ level. The evolution of beneficial traits that enhance reproductive success is an example of how genetics affects a species at the ______ level.
molecular; population
A group of organisms that maintains a distinctive set of attributes is called a(n)
species or specie
What are alleles?
Alternative versions of the same gene
Differences in inherited traits among individuals within a population are referred to as genetic
variation, diversity, variability, variations, or variance
The genetic variation among individuals within a population can be explained by differences in the sequence of
DNA
How do alleles differ from one another?
They have slightly different DNA sequences.
Which of the following are genomic alterations that may induce genetic variation?
Changes in chromosome number
Gene mutations
Changes in chromosome structure
Changes in the nucleotide sequence of a single gene that result in two or more alleles for that gene are called gene
mutations
Genetic variation describes differences in ______.
inherited traits among individuals within a population
True or false: All gene mutations that have an effect on a cell or organism alter the structure and function of the protein encoded by the gene.
False
What underlies the majority of the genetic variation among individuals within a population?
Differences in the nucleotide sequence of DNA
Down syndrome is the result of ______.
a change in total chromosome number
True or false: An organism's environment can affect its morphological and physiological traits.
True
Reason:
Both genes and the environment can influence an organism's traits.
Genetic variation can be attributed to gene ____ that affect the sequence of a single gene or alterations in the structure or total number of ____.
mutations; chromosomes
What is a gene mutation?
A change in the base pair sequence of a gene
Gene mutations can affect the traits of an organism because they can alter the expression or function of the ____ encoded by the gene.
protein, proteins, or polypeptide
The term diploid means that a cell or organism has ______.
two copies of every chromosome
Variation in human eye color is due to ______.
variation of sequences within genes
Reason:
Changes in chromosome number often cause harmful changes rather than producing harmless variations such as differing eye colors.
Reason:
Changes in chromosome structure often cause harmful changes rather than producing harmless variations such as differing eye colors.
An organism's traits can be affected by its genes and also by its
environment
In this figure, two copies of chromosome 13 are circled. These two copies of chromosome 13 are called of each other.
homologs, homologues, homologous, or homolog
Which of the following are genomic alterations that may induce genetic variation?
Changes in chromosome structure
Gene mutations
Changes in chromosome number
The two chromosomes in a homologous pair contain ______.
copies of the same genes, which may or may not be identical alleles
A cell or organism that contains two copies of every chromosome is said to be
diploid or somatic
In a multicellular organism, cells that are not directly involved in sexual reproduction are called ____ cells.
somatic
How many chromosomes would be found in a diploid human cell?
46
In a diploid organism, the two copies of a chromosome are referred to as ______.
homologs
A human sperm cell contains ______ chromosome(s).
23
Which of the following cells are gametes?
Sperm
Egg
True or false: A pair of homologous chromosomes always contains identical alleles of the same genes.
False
A cell that contains a single set of chromosomes is called
haploid or monoploid
What are somatic cells?
Cells that are not involved in sexual reproduction
A human somatic cell contains ____ chromosomes.
46
A human egg cell would contain ____ chromosomes.
23
The union of gametes at fertilization restores ______.
the diploid number of chromosomes
Sperm and egg cells are also called ______.
gametes
What is the primary advantage of sexual reproduction over asexual reproduction?
Sexual reproduction enhances genetic variation.
A cell that is haploid contains ______ set(s) of chromosomes.
1
Changes in the genetic makeup of a population from one generation to the next represent
evolution, microevolution, or biological evolution
In a multicellular organism, cells that are not directly involved in sexual reproduction are called ____ cells.
somatic
An allele that improves the ability of individuals to survive and reproduce may become more prevalent in future generations due to
natural selection
Match each model organism shown in the image to the correct name.
During sexual reproduction, the process in which gametes unite to restore the diploid number of chromosomes is called
fertilization
The inheritance of genes and the way that genes influence traits is the focus of ____ genetics.
transmission
One of the main advantages of sexual reproduction is that it increases ____ variation.
genetic
How are genes passed from parents to offspring?
In sperm and egg cells
What is evolution?
Change in the genetic makeup of a population from one generation to the next
The breeding of two selected individuals and the analysis of their offspring is referred to as ______.
a genetic cross
After a random mutation creates a new allele that may be harmful, neutral or beneficial, which of the following may occur during natural selection?
A beneficial allele may become more prevalent in future generations
Individuals carrying a beneficial allele are more likely to reproduce and pass on the allele
Which area of genetics focuses on the biochemical understanding of DNA and gene expression?
Molecular genetics
Match the scientific name of each organism with its common name.
The term genetic approach refers to the study of ______.
mutant genes with abnormal function
Which field of genetics focuses on how genes are passed on from parents to offspring?
Transmission genetics
A mutation that eliminates the function of a gene is called a(n) -___ of- ___ mutation.
loss; function
Mendel proposed that factors, which we now call ____ , are passed from parents to offspring via sperm and egg cells.
genes
If fruit flies normally have red eyes and a loss-of-function mutation in a certain gene results in white eyes, then the role of the normal gene is the production of pigment that is ___ in color.
red
What is a genetic cross?
The breeding of two individuals and the analysis of their offspring
The field of genetics that focuses on the relationship of genetic variation to an organism's environment is called genetics.
population
Which of the following topics is the focus of molecular genetics?
The biochemical structure and function of DNA
Which approach involves implementation of the scientific method to test an explanation for a natural phenomenon?
Hypothesis testing
The study of mutant genes with abnormal function in order to better understand the function of a normal gene is referred to as a(n) ___ approach.
genetic
Because genetics is a quantitative science, researchers often rely on methods to analyze the data and make conclusions.
statistical or mathematical
A loss-of-function mutation is a mutation that ______.
eliminates the function of a gene
One useful strategy for solving problems in genetics is to propose a(n) ____, which is an attempt to explain an observation or data.
hypothesis
If a plant normally produces red flowers and a loss-of-function mutation within a certain gene results in production of white flowers, what is the role of the functional gene?
Production of red pigments
What is the focus of population genetics?
The relationship between genetic variation and an organism's environment
What is the difference between hypothesis testing and discovery-based science?
Discovery-based science does not require a preconceived hypothesis.
You are studying genetic data about the prevalence of a disease from a large family, but it is not organized in any particular way. To better understand the data, which genetics problem solving strategy should you employ?
Make a drawing
You are trying to solve a genetics problem that asks you to determine how two proteins differ from one another. Which problem-solving strategy would be most helpful for this question?
Compare and contrast