Inherited Change Terms

Question 1

Genetics:

Answer 1

The study of genes, genetic variation, and heredity in living organisms.[

Question 2

Homologous:

Answer 2

Pair of c.s. in a diploid cell that have the same structure as each other,
with the same genes (but not necessarily the same alleles of those genes) at the same loci,
and that pair together to form a bivalent during the first division of meiosis.

Question 3

A gene:

Answer 3

A gene is a length of DNA that codes for a particular protein or polypeptide.

Question 4

An allele:

Answer 4

Particular variety of a gene.

Question 5

A locus

Answer 5

The position at which a particular gene is found on a particular chromosome; the same gene is always found at the same locus.

Question 6

A diploid cell:

Answer 6

Cell that possesses two complete sets of chromosomes; 2n.

Question 7

A haploid cell:

Answer 7

A cell that possesses one complete set of chromosomes; n.

Question 8

A genotype:

Answer 8

The alleles possessed by an organism.

Question 9

Phenotype:

Answer 9

An organisms characteristics, often resulting from an interaction between its genotype and its environment.

Question 10

How does genotype affect phenotype?

Answer 10

A

Question 11

Homozygous:

Answer 11

Having two identical alleles of a gene.

Question 12

Heterozygous:

Answer 12

Having two different alleles of a gene.

Question 13

A dominant allele:

Answer 13

One whose effect on the phenotype of a heterozygote is identical to its effect in a homozygote.

Question 14

A recessive allele:

Answer 14

One that is only expressed when no dominant allele is present.

Question 15

Codominant alleles:

Answer 15

Codominant alleles both have an effect on the phenotype of a heterozygous organism.

Question 16

The F1 generations:

Answer 16

The offspring resulting from a cross between an organism with a homozygous dominant genotype, and one with a homozygous recessive genotype. ?????

Question 17

The F2 generations:

Answer 17

The F2 generation is the offspring resulting from a cross between two F1 (heterozygous) organisms. ????

Question 18

A testcross:

Answer 18

A genetic cross in which an organism showing a characteristic caused by a dominant allele is crossed with an organism that is homozygous recessive; the phenotypes of the offspring can be a guide to whether the first organism is homozygous or heterozygous.

Question 19

Linkage:

Answer 19

The presence of two genes on the same chromosome, so that they tend to be inherited together and do not assort independently.

Question 20

Genetic diagrams:

Answer 20

A

Question 21

The punnets square:

Answer 21

A

Question 22

Pedigree:

Answer 22

A

Question 23

The chi-squared test:

Answer 23

A statistical test
that allows us to compare our observed results (O) with the expected results (E) and to know whether or not there is a significant difference between them.u

Question 24

Frameshift mutation:

Answer 24

Occurs when the
addition or loss of DNA bases changes a gene’s reading frame.
A frameshift mutation shifts the grouping of these bases and changes the code for amino acids. The resulting protein is usually nonfunctional. Insertions,
deletions, and duplications can all be frameshift

Question 25

Missenes Mutation:

Answer 25

This type of mutation is a change in one DNA
base pair that results in the substitution of one amino acid for another in the protein made by a gene.

Question 26

Nonsense Mutation:

Answer 26

A change in
one DNA base pair. Instead of substituting one amino acid for another, however, the altered DNA sequence prematurely signals the cell to stop building a protein. This type of mutation results in a shortened protein that may function improperly or not at all.

Question 27

Pleiotropy:

Answer 27

The situation in which a single gene is responsible for a variety of traits. The collective group of symptoms known as sickle-cell trait is an example.

Question 28

Sickle cell anemia:

Answer 28

A genetically inherited recessive condition in which red blood cells
are distorted and stop working. Sickle-cell trait is the result of a pleiotropic gene. Sickle-cell trait is also known as sickle-cell anemia.

Question 29

Albinism:

Answer 29

The genetically inherited condition in which there is a marked deficiency of
pigmentation in skin, hair, and eyes.
Since the gene for albinism is recessive, it only shows up in the
phenotype of homozygous recessive people. This is a pleiotropic trait.

Question 30

HD:

Answer 30

severe genetically inherited fatal degenerative nerve disorder.
The symptoms usually do not appear until early middle age. There is a progressive loss
of muscle control that inevitably leads to paralysis and death.

Question 31

Promoter:

Answer 31

– DNA sequence at which RNA polymerase binds and initiates transcription
– In genetics, a promoter is a region of DNA that initiates transcription of a particular
gene. Promoters are located near the transcription start sites of genes, on the same strand and
upstream on the DNA (towards the 5’ region of the sense strand).

Question 32

Terminator:

Answer 32

– In genetics, a transcription terminator is a section of nucleic acid sequence that marks the end of
a gene or operon in genomic DNA during transcription.
• This sequence mediates transcriptional termination by providing signals in the newly
synthesized mRNA that trigger processes which release the mRNA from the transcriptional
complex. These processes include the direct interaction of the mRNA secondary structure with
the complex and/or the indirect activities of recruited termination factors. Release of the
transcriptional complex frees RNA polymerase and related transcriptional machinery to begin
transcription of new mRNAs.

Question 33

Operator:

Answer 33

An operator is a segment of DNA to which a transcription factor binds to regulate gene
expression.

Question 34

DNA binding sites:

Answer 34

A short DNA sequences (typically 4 to 30 base pairs long, but up to 200 bp for
recombination sites) that are specifically bound by one or more DNA-binding proteins or protein
– Found in DNA where other molecules may bind. DNA binding sites are distinct from other binding
– (1) they are part of a DNA sequence (e.g. a genome) and
– (2) they are bound by DNA-binding proteins.
– DNA binding sites are often associated with specialized proteins known as transcription factors, and
are thus linked to transcriptional regulation.

Question 35

Transcription factors:

Answer 35

Proteins that bind to a specific sequence in DNA and control the flow of information
from DNA to RNA by controlling the mRNA synthesis.
• The transcription factor is a repressor, which can bind to the operator to prevent transcription.
– The repressor protein physically obstructs the RNA polymerase from transcribing the genes.

Question 36

Enhancer:

Answer 36

An enhancer is a short DNA sequence that increases the level of expression of another gene,
that is, the enhancer up-regulates transcription of genes within the regulated gene-cluster.
• An inducer (small molecule) can displace a repressor (protein) from the operator site (DNA), resulting in an
uninhibited operon.

Question 37

Lac operon:

Answer 37

An operon is length of DNA making up a unit of gene
expression in a bacterium.
– Or In genetics, an operon is a functioning unit of genomic DNA
containing a cluster of genes under the control of a single promoter.
• It consists of one or more structural genes and also control regions of DNA that are
recognised by the product of regulatory genes.

Question 38

Structural genes:

Answer 38

Genes that code for a protein required by a cell are called
structural proteins such proteins may form part of cellular structures, but they
may function have some other functions such as enzymatic
• For example: In the lac-Operon concept, these genes are associated with the
synthesis of those enzymes that are needed for the catabolism of Lactose. In
lac-operon, there are three structural genes:
a. Lac Z gene for beta-galactosidase enzyme.
b. Lac Y gene for permease enzyme (which allow to enter lactose the cell)
c. Lac A gene for acetylase enzyme.

Question 39

Regulatory genes:

Answer 39

Gene that code for proteins that regulate the expression of
other genes (by controlling the production of a protein as a genetic repressor,
which regulates their rate of transcription) are called regulatory genes.

Question 40

Mutation:

Answer 40

• Mutation - is an unpredictable change in the genetic material of an organism.
• A change in the structure of a DNA molecule, producing a different allele of a gene, is a gene mutation.
• Chromosome mutation.

Question 41

Autosomal linkage:

Answer 41

A

Question 42

Crossing over:

Answer 42

A

Question 43

Repressible and inducible enzymes

Answer 43

Repressible and inducible enzymes
– The synthesis of repressible enzymes can be prevented by binding to a repressor protein
to a specific site, called an operator, on a bacterium DNA
– The synthesis of an inducible enzyme occurs only when its substrate is present.
Transcription of the gene occurs as a result of the inducer (the enzymes substrate)
interacting with a protein produced by the regulatory gene.

Question 44

Independent assortment:

Answer 44

A