genetic inheritance

What is gamete?

Reproductive cell-carries half the genetic material

what is zygote?

Fertilized egg cell-containing a full set of genetic material

What is diploid?

Two complete sets of chromosomes

What is haploid?

Only has one set of chromosomes

Why do diploid cells have two copies of each autosomal gene?

-They inherit one copy, each from one parent

-Each gene comes from one parent, giving the organism two copies of each gene

What is gene?

Segment of DNA that carries instructions for a specific trait or function

What is allele?

Variation or form of a gene

Compare and contrast the different alleles of the same gene

-A is the dominant allele, and a, a recessive allele

-The dominant allele will determine the trait is present even if one copy is inherited

-The recessive allele will only show its effect if two copes (aa) are inherited

What is genotype?

The genetic makeup of an organism representing the allele it inherits from its parents

What is phenotype?

The physical appearance or traits of an organism, resulting from the interaction of its genotype

What is a phenotype in humans that is due to genotype only?

Blood type - determined by the specific alleles inherited from both parents

what is a phenotype in humans that is due to the environment only?

Skin color- because of sun exposure

what is a phenotype in humans that is due to the interaction of genotype and the environment?

Height- because of nutrition and health

What is a dominant allele?

Expresses it’s traits even if only one copy is present

What is a recessive allele?

Expresses it’s traits only if two copies are present

What is the usual cause of one allele being dominant over the other

-One allele is usually dominant over another because it makes a working protein

-while the recessive allele either makes a non-working protein or none at all

What is P?

-Parental generation

-The first set of parents in a genetic cross

What is F1?

Off spring in P generation

What is F2?

Off spring of F1 generation after crossing or self-fertilization

what is homozygous?

-When an organism has two identical alleles for a gene

-(AA or aa)

What is heterozygous?

-When an organism has two different alleles for a gene

-(Aa or aA)

What is genotype?

The genetic makeup of an organism representing the alleles it inherits from it’s parents

What is phenotype?

The physical appearance or traits of an organism, resulting from the interaction of it’s genotype

What is a phenotype in humans that is due to genotype only?

-Blood type

-Determined by the specific alleles inherited from both parents

What is a phenotype in humans that is due to the environment only?

-Skin color because of sun exposure

What is a phenotype in humans that is due to the interaction of genotype and the environment

-Height because of nutrition and health

What is a dominant allele?

Expresses it’s trait even if only one copy is present

What is a recessive allele?

-Expresses it’s traits only if two copies are present

What is P, F1, AND F2.

-P-Parental generation the first set of parents in a genetic cross

-F1- Offspring in P generation

-F2-Offspring of F1 generation after crossing

What is the process of experimentally performing a genetic cross in flooring plants using cross pollination and self-fertilization?

-Cross pollination:(D→F1)

-Select two plants with different traits

-

What is the purpose of reforming genetic crosses in plants?

To develop new hybrid plants

What are possible alleles present in gametes given parent genotypes?

-Identify parent genotype

-Separate alleles

-List possible gametes

What is “Carrier” as related to genetic diseases?

A person who has one normal allele and one mutated allele for a recessive genetic disease

Why does genetic diseases often appear unexpectedly in a population?

When two carries have children there is a chance the child inherits two mutated allies leading to the disease

What is the genetic cause of phenylketonuria?

A mutation in the PAH gene

What are the consequences of phenylketonuria if untreated?

-Brain damage and intellectual disability

-Seizures

-Behavioral problems

-Delayed development

-Skin issues

-Musty odor

How is phenylketonuria treated?

Strict low- phenlalaine diet

What is a codominant allele?

Both alleles are equally expressed in the phenotype (blood type)

What is an incomplete dominant allele?

Alleles blend together to create an immediate phenotype

New alleles of a gene are the results of mutation

New alleles of a gene are the results of mutation

What is a single-nucleotide polymorphism?

- a variation in a single nucleotide base pair in the DNA sequence among individuals of species

-It can lead to differences in traits or risk to disease

What is a gene pool?

-Total collection of a genetic material (alleles) present in a population of a species

-It includes all the variations of genes that can be passed down to future generations

Why can any number of allele of a gene can exist in the gene pool but an individual only gains ten alleles?

-An individual only inherits two alleles for each gene, one from each parent

-They receive one set of chromosomes from their mother and one set from their father

How does the multiple alleles of the S-gene in the apple gene pool are a mechanism for preventing self-pollination?

-Multiple alleles: The s-gene has many different alleles in the gene pool, and each apple tree carries two alleles for this gene

-S-allele interaction: If both alleles in a tree are homozygous, the trees can’t produce viable pollen, preventing self-pollination

-Genetic incompatibility: For successful pollination, the s-alleles of the polls and the sigma must be different

What are ABO blood groups as an example of complete dominance?

-The A (IA) and B (IB) alleles are completing dominant over the O (I) allele

-If a person inherits IAi or IBi, they will have blood type A or B because the O allele doesn't express any antigens

What are ABO blood groups as an example of complete codominance?

-When a person inherits both IA and IB alleles both are expressed equally=blood type AB

-Both alleles contribute to the phenotype without one being dominant over the other

What is sex-linkage?

-Traits controlled by genes on sex chromosomes

-X or Y

What is an example of the inhertrce of hemophilia using the correct notation?

-X^h=Hemophilla allele

-X^H=Normal allele

-Y=male chromosome (unaffected)

What is the pattern of inheritance for sex linked genes?

-X linked recessive traits are more common in males (xy) because they only have one X chromosome

-Females are (xx) can be carriers but need two affected X’s to express the trait

What Is the cause of hemophilia?

-Caused by a mutation in the X chromosome, affecting blood clotting

-Results in excessive bleeding due to inproper clotting

What are the conventions for constructing pedigree charts?

-Squares represent males

-Circles represent females

-Shaded symbols indicate individuals with the affected trait

-Unshaded symbols indicate individuals without the trait

-Horizontal lines connect mates

-Vertical lines connect parent offspring

-IV roman numerals label generation

-Arabic numbers label individuals within a generation

What is a mutation?

Changes in the DNA sequence of an organisms genes

What is base substitution?

-One base in the DNA is replaced with another

-Can change a single amino acid in a protein

-No affect on the protein

What is base insertion?

-One or more extra bases are added to the DNA sequence

-Can lead to shifting the reading frame which —> completely different amino acid sequence in the resulting protein

What is base deletion?

-One or more bases are removed form the DNA sequence

-Can shift the reading frame and alter the protein

What are causes of gene mutations?

-Spontaneous mutations which happen naturally during DNA replication or cell division (No outside influence)

-Mutagens which are external factors like: Chemicals, radiation, or viruses (damages the DNA and cause mutations)

-Errors in DNA repair is when the cells repair mechanisms fail, leading to changes in the DNA sequence.

What is a mutagen?

-Any substance or agent that causes changes in the DNA of the organism

-So like chemicals, radiation, viruses

What is the impact of randomness of gene mutations?

Many mutations have no noticeable effect on an organism as they don’t change it’

No natural mechanism is known for making a deliberate change to a DNA sequence

No natural mechanism is known for making a deliberate change to a DNA sequence

What is a single-nucleotide polymorphism?

-A variation in a single base pair in the DNA sequence

-Occurs when one nucleotide (A, T, C, G) is replaced by another nucleotide

Compare the impact of base substitution mutation in coding and non coding sequences of DNA

-Coding sequences: Change the protein that’s made potentially altering it’s function

Leads to diseases or new traits if it affects the important parts

-Non-coding sequences: Affect gene regulation or how genes are expressed, don’t usually change the protein it’s self

What is the impact of genetic code degeneracy on the effect of mutations?

-If a mutation changes a codon to another trait that still codes for the same amino acid, no affect

-many amino acids are coded by more than one codon, some mutations won’t cause a change in the proteins functions

Explain same-sense, nonsense and mis-sense base substitution mutations.

-Same sense (silent): Mutation changes base, but new codon still codes for the same amino acid (meaning no change)

-Nonsense: Mutation changes a codon into a “Stop” codon, leading to a premature termination of protein synthesis (meaning non-functional)

-Mis-sense: changes a codon, causing it to code for a different amino acid (meaning alters protein function)

What is a “frameshift” mutation?

A genetic mutation caused by insertions or deletions of nucleotides that shifts the reading frame of the codons. This often leads to significant changes in the resulting protein, potentially resulting in nonfunctional proteins.

What are the consequences of insertions and deletions on polypeptide structure and function?

Insertions and deletions can cause frameshift mutations, which alter the reading frame of codons, leading to changes in the amino acid sequence. This can result in polypeptides that are nonfunctional or have altered functions.

What is gene mutation?

A change in the DNA sequence of a gene

What is the cause of sickle cell anemia including differences in the HbA and HbS alleles.

-Caused by a mutation in the HBB gene- changes the normal HBA allele to the sickle cell HBS

-HbA: allele makes normal hemoglobin

-HbS: allele has a single base change, causing one amino acid to be replaces with valine

What is the difference in RNA sequences in the transcription of the HbA and HbS alleles?

-HBA RNA has GAG- codes for glutamic acid

-HBS RNA has GUG- codes for valine

What is the difference in amino acid sequences in the translation of the HbA and the HbS alleles?

-HBA makes glutamic acid at position 6 of the beta-globin chain

-HBS makes valine at the same position

What are the consequences of the HbS mutation on the structure and the function of the hemoglobin protein?

-Structure: hemoglobin molecules stick together, forming long fibers that distort red blood cells into sickle cell shape “C”

-Function: The sickled cells carry less oxygen and can block blood flow in small vessels

What are the symptoms of sickle cell disease?

-Sudden severe pain due to blocked blood flow

-Fatigue and weakness from low red blood cells

-Swelling in hands and feet

-Frequent infections

-Vision problems

-shortness of breath

What is epigenesis and epigenome?

-Epigenesis: How genes are turned on or off during development, affecting how traits are expresses without changing the DNA sequence

-Epigenome: the set of chemicals tags on DNA and histones that control gene activity

What is the impact of methylation of DNA in the promoter of DNA on gene expression?

It usually turns of the gene. It blocks transcription factors from binding, so the gene is not expressed

What is the impact of acetylation and methylation of histone proteins on gene expression?

-Acetylation: histone proteins turns genes on by loosing DNA, making it easier for transcription to happen

-Methlaytion: Histones can turn genes on or off, depending on where it happenes on the histone

What is the inheritance of epigenetic tags in differentiated cells of a multicellular organism?

-Differentiated cells inherit epigenetic tags during cell division

-It helps each cell type keep its specific pattern and function

What are the consequences of reprogramming and imprinting of epigenetic tags in haploid gametes?

-can lead to the resetting of epigenetic tags in gametes

-it ensures that genes are expressed appropriately according to parental origin and developmental stage, affecting offspring traits.

What is the impact of air pollution on the epigenetic regulation of genes associated with the immune response?

Can change epigenetic tags like DNA methylation on immune- related genes. This can turn off or on genes at the wrong time

How does imprinting of genetic tags impact gene expression in a diploid cell?

-If a gene is paternally imprinted, the fathers allele is silenced, and the mothers allele is expresses

-maternally: mothers allele is silenced, and fathers allele is expressed