Comprehensive Genetics, Evolution, and Biotechnology Concepts

What is heredity?

The passing of characteristics from parent to offspring through the parent's genes.

What is selective breeding?

A method that allows breeders to observe heredity and select for specific traits, such as reduced size in horses.

What are single-gene traits?

Traits determined by the instructions carried on one gene, exhibiting straightforward patterns of inheritance.

How do most human characteristics arise?

Most human characteristics are influenced by multiple genes and the environment.

What is Mendel known for?

conducting experiments in the mid-1800s that helped understand heredity, focusing on traits in garden peas.

What is Mendel's Law of Segregation?

The principle stating that only one of the two alleles for a gene is put into a gamete, and offspring receive one allele from each parent.

What is the difference between phenotype and genotype?

Phenotype is the outward appearance of an individual, while genotype is the genetic composition for a particular trait.

What does a Punnett square do?

a tool used to determine the possible genetic outcomes of a cross between two individuals.

What is the significance of dominant and recessive traits?

A dominant trait masks the effect of a recessive trait when both are present in an individual.

What is the phenotypic ratio expected from a monohybrid cross?

The expected phenotypic ratio is typically 3:1 for dominant to recessive traits.

What is a test-cross?

A breeding experiment used to determine the genotype of an individual exhibiting a dominant trait by crossing it with a homozygous recessive individual.

What role do antigens play in the immune system?

chemicals on the surface of cells that signal to the immune system whether the cell belongs in the body.

What are antibodies?

immune system molecules in the bloodstream that attack cells with foreign antigens.

What is the blood type compatibility for type O blood?

Individuals with type O blood are universal donors, as they have no A or B antigens.

What is the blood type compatibility for type AB blood?

Individuals with type AB blood are universal recipients, as they have both A and B antigens and no antibodies against them.

What is the probability of inheriting Tay-Sachs from two heterozygous parents?

There is a 25% chance that a child will inherit Tay-Sachs disease from two heterozygous parents.

How does chance affect genetic outcomes?

Chance plays a role in segregation and fertilization, making it impossible to predict the exact allele that will be passed on.

What is the significance of the homunculus theory?

a mistaken idea that a tiny, pre-made human existed in every sperm cell, popular until the 1800s.

What does it mean for a trait to be homozygous?

when they have two identical alleles for that gene.

What does it mean for a trait to be heterozygous?

when they have two different alleles for that gene.

What is the role of segregation in genetics?

ensures the two copies of each gene an individual carries.

What is the expected outcome of a cross between a homozygous dominant and a homozygous recessive individual?

All offspring will be heterozygous and exhibit the dominant trait.

What is the expected outcome of a cross between two heterozygous individuals?

The expected phenotypic ratio is 3:1, with three exhibiting the dominant trait for every one exhibiting the recessive trait.

What determines the presence of the Rh marker?

A single gene with two alleles.

What are the two types of Rh blood types?

Rh-positive (one or two copies of the dominant allele) and Rh-negative (two copies of the recessive allele).

What is multiple allelism?

A single gene having more than two alleles in a population, such as the ABO blood groups in humans.

What is pleiotropy?

When one gene influences multiple, unrelated traits.

How does the allele for sickle-cell disease demonstrate pleiotropy?

It causes red blood cells to form a sickled shape and provides resistance to malaria.

What are the genotypes and malaria susceptibility for HbAHbA homozygotes?

They produce no sickling cells, do not have sickle-cell disease, and are susceptible to malaria.

What is the genotype and malaria immunity for HbSHbA heterozygotes?

They produce some sickling cells but not enough to have sickle-cell disease and are immune to malaria.

What is the genotype and malaria immunity for HbSHbS homozygotes?

They produce sickling red blood cells, have sickle-cell disease, and are immune to malaria.

What does Mendel's law of independent assortment state?

The inheritance of one trait does not influence the inheritance of another trait.

What is a dihybrid?

An individual who is heterozygous for two traits.

What is a dihybrid cross?

A mating between two individuals that are both heterozygous for two traits.

What is DNA?

A molecule that contains the instructions for the functions of every cell in living organisms.

What are the three components of a nucleotide?

A phosphate group, a sugar, and a nitrogen-containing base.

What is the structure of DNA often described as?

A twisted ladder, with sugar and phosphate groups as the backbones and base pairs as the rungs.

What are the base pairing rules in DNA?

Adenine pairs with thymine, and guanine pairs with cytosine.

What is a genome?

An organism's complete set of DNA.

What is a chromosome?

One or more unique pieces of DNA that vary in length and can consist of hundreds of millions of base pairs.

What is a gene?

A specific sequence of DNA that contains the information necessary for protein synthesis.

What are alleles?

Different versions of a gene that code for the same trait.

What is the significance of noncoding DNA in eukaryotes?

Eukaryotes have a large amount of noncoding DNA, which does not code for proteins.

What percentage of DNA codes for proteins in humans?

Approximately 28%.

What is 'junk DNA'?

A term often used to refer to noncoding DNA, though it is now understood that much of this DNA has important regulatory functions.

What is the role of genes in organisms?

provide the instructions for building virtually every organism on earth.

How many unique chromosomes do humans have?

Humans have 23 unique chromosomes, with two copies of each.

What are introns?

Noncoding regions within genes that do not code for proteins.

What percentage of noncoding DNA occurs between genes?

75% of noncoding DNA occurs between genes.

What is the genotype?

The genes that an organism carries for a particular trait.

What is the phenotype?

The physical manifestation of the genes for a particular trait.

What are the two main steps in the process of gene expression?

Transcription and Translation.

What occurs during transcription?

The gene's sequence is copied from DNA to mRNA.

Where does transcription occur in eukaryotic cells?

In the nucleus.

What is the role of RNA polymerase in transcription?

RNA polymerase recognizes a promoter site, binds to DNA, and synthesizes mRNA.

What happens to mRNA after transcription in eukaryotes?

mRNA receives a cap and tail for protection and noncoding sections are removed.

What is the purpose of the cap and tail added to mRNA?

To protect the mRNA and promote recognition during translation.

What is translation?

The process where the mRNA sequence is used to build a protein.

What is a codon?

A three-base sequence on mRNA that matches with a tRNA carrying a specific amino acid.

What signifies the start of translation?

The 'START sequence' of the mRNA, signified by the bases A, U, and G.

What happens during the elongation phase of translation?

The ribosome moves along the mRNA, adding amino acids to the growing protein chain.

What signals the termination of translation?

The ribosome encounters a 'STOP sequence' on the mRNA.

How often can the same mRNA molecule be translated?

The same mRNA molecule can be translated multiple times before degradation.

What is gene expression?

The production of the protein that the gene's sequence codes for.

What is gene regulation?

The control over whether a gene is turned on or off.

What factors can influence gene expression?

Environmental factors can have regulatory effects on gene expression.

What is the function of tRNA in translation?

tRNA molecules translate the mRNA code by linking specific bases on the mRNA with specific amino acids.

What is the relationship between DNA, mRNA, and proteins?

DNA contains the instructions, mRNA is the copy that carries those instructions, and proteins are the functional products made from those instructions.

What are transcription factors?

Proteins that bind to specific regulatory sites on DNA to control gene expression.

What is positive control in gene expression?

A mechanism that initiates or speeds up gene expression.

What is negative control in gene expression?

A mechanism that slows or blocks gene expression.

What is an operon?

A group of several genes along with the elements that control their expression as a unit, all within one section of DNA.

What are the three main components of an operon?

Promoter, operator, and regulatory gene.

What happens to the lac operon when lactose is present?

The operon is turned on, allowing RNA polymerase to transcribe genes necessary

What is the role of a repressor protein in the lac operon?

It binds to the operator to prevent RNA polymerase from transcribing the genes when lactose is not present.

What is transcription regulation?

The control of gene expression at the transcription stage, involving activators, repressors, and enhancer sequences.

What is post-transcription regulation?

Control of gene expression after transcription, affecting mRNA processing, transport, and degradation.

What is a mutation?

An alteration to the sequence of bases in DNA that can be detrimental, beneficial, or neutral.

What are point mutations?

Changes in a single nucleotide in the DNA sequence, which can include substitutions, insertions, or deletions.

What are chromosomal aberrations?

Alterations that affect entire sections of a chromosome, such as gene relocation or duplication.

What causes spontaneous mutations?

Accidental changes that occur during DNA replication.

What are environmental factors that can cause mutations?

Radiation and chemicals that induce changes in DNA.

What is biotechnology?

The use of technology to modify organisms, cells, and their molecules for practical benefits.

What are the primary areas where biotechnology is applied?

Agriculture, human health, and forensic science.

What is the first step in isolating a gene of interest using restriction enzymes?

Chopping up DNA from a donor species that exhibits a trait of interest.

What is the purpose of the Polymerase Chain Reaction (PCR)?

To amplify small samples of DNA into more useful quantities.

How does DNA polymerase function in PCR?

It adds complementary bases to each single strand of DNA after heating and separating the strands.

What is the role of plasmids in biotechnology?

They are used to transfer DNA from one organism to another.

What is the significance of enhancer sequences in gene regulation?

They can speed up RNA polymerase binding and gene transcription.

What is the effect of mutations on proteins?

Mutations can change the protein produced by the altered gene, potentially leading to loss of function.

What is a neutral mutation?

A mutation that has no positive or negative effect on the organism.

How can mutations contribute to evolution?

They introduce genetic variation, which can be acted upon by natural selection.

What is the purpose of using restriction enzymes in biotechnology?

Restriction enzymes are used to cut DNA at specific sequences, allowing for the insertion of genes into plasmids.

How is a gene library created?

by chopping DNA into pieces, inserting each piece into a plasmid, and introducing each plasmid into different bacterial cells, which then replicate the DNA.

What is CRISPR and its significance in biotechnology?

CRISPR is a gene editing system that allows for precise and efficient modification of DNA, enabling researchers to alter almost any gene in any organism.

What does the RNA guide do in the CRISPR process?

The RNA guide matches the target gene sequence and directs the Cas9 enzyme to the specific location on the DNA to make a cut.

What are some potential applications of CRISPR technology?

CRISPR can be used to alter mosquito DNA to block malaria, modify white blood cells to fight cancer, and create genetically modified animals with enhanced traits.

What are some ethical concerns associated with CRISPR?

Ethical concerns include the potential for editing human embryos and germline cells, as well as the unpredictable consequences of introducing altered genes into natural populations.

What is genetic engineering?

Genetic engineering is the manipulation of an organism's genome in ways that do not occur naturally, often using recombinant DNA technology.

How has biotechnology improved agriculture?

Biotechnology has led to the development of transgenic plants and animals that produce more nutritious food and have reduced environmental and financial costs.