What is a gene Bioninja?

A gene is a heritable factor that consists of a length of DNA and influences a specific characteristic. A gene occupies a specific position on a chromosome. The various specific forms of a gene are alleles. Alleles differ from each other by one or only a few bases. New alleles are formed by mutation.

What is meiosis Bioninja?

Meiosis consists of two divisions, both of which follow the same stages as mitosis (prophase, metaphase, anaphase, telophase) Meiosis is preceded by interphase, in which DNA is replicated to produce chromosomes consisting of two sister chromatids.

What is the effect of dominant alleles IB?

What is the effect of dominant alleles? I. They mask the effect of recessive alleles.

What are the characteristics of haploid and diploid numbers of eukaryotic chromosomes?

The sex cells, or gametes, of sexually-reproducing eukaryotic organisms are haploid (1n), meaning they only have 23 unpaired chromosomes. When a sperm cell fertilizes an egg, the resulting zygote is diploid; the combination of the two haploid sex cells is what results in the zygote having the full 46 chromosomes.

What are the steps to transcription Bioninja?

Transcription

1. RNA polymerase separates the DNA strands and synthesises a complementary RNA copy from one of the DNA strands.
2. When the DNA strands are separated, ribonucleoside triphosphates align opposite their exposed complementary base partner.

How are mutations caused Bioninja?

Examples of factors which can induce mutations include: Radiation – e.g. UV radiation from the sun, gamma radiation from radioisotopes, X-rays from medical equipment. Chemical – e.g. reactive oxygen species (found in pollutants), alkylating agents (found in cigarettes)

What is mitosis Bioninja?

Mitosis is the process of nuclear division, whereby duplicated DNA molecules are arranged into two separate nuclei. Mitosis is preceded by interphase and is divided into four distinct stages: prophase, metaphase, anaphase, telophase.

What is crossing over Bioninja?

• Crossing over is the exchange of DNA material between non-sister homologous chromatids. • Crossing over produces new combinations of alleles on the chromosomes of the haploid cells. When chiasmata form between bivalents in prophase I, DNA can be exchanged between non-sister homologous chromatids.

What is Codominance Bioninja?

Co-dominance Co-dominance occurs when pairs of alleles are both expressed equally in the phenotype of a heterozygous individual. Heterozygotes therefore have an altered phenotype as the alleles are having a joint effect.

Why are IA and IB alleles dominant?

The IA allele codes for A molecules on the red blood cells, the IB allele codes for B molecules on the surface of red blood cells, and the i allele codes for no molecules on the red blood cells. In this case, the IA and IB alleles are codominant with each other and are both dominant over the i allele.

What is difference between haploid and Monoploid?

Monoploids have a single basic set of chromosomes e.g. 2n = x = 7 in barley or 2n = x = 10 in corn. Haploids, on the other hand represent individuals having half the somatic chromosome number found in normal individual. Therefore, individuals having 2n = 3x = 21 in wheat would also be haploids(not monoploid).

What are homologous chromosomes Bioninja?

Homologous chromosomes are chromosomes that share: The same structural features (e.g. same size, same banding patterns, same centromere positions) The same genes at the same loci positions (while the genes are the same, alleles may be different)

What is DNA transcription Bioninja?

Transcription is the process by which a DNA sequence (gene) is copied into a complementary RNA sequence by RNA polymerase. Free nucleotides exist in the cell as nucleoside triphosphates (NTPs), which line up opposite their complementary base partner.

What is a codon Bioninja?

Codons. The base sequence of an mRNA molecule encodes the production of a polypeptide. The mRNA sequence is read by the ribosome in triplets of bases called codons. Each codon codes for one amino acid with a polypeptide chain.

What is evolution Bioninja?

Evolution is the cumulative change in the heritable characteristics of a population across successive generations. This requires that allele frequencies change within the gene pool of the population to reflect these evolving characteristics.

How is the cell cycle controlled Bioninja?

Cyclins are involved in the control of the cell cycle.

What is endocytosis Bioninja?

Endocytosis. The process by which large substances (or bulk amounts of smaller substances) enter the cell without crossing the membrane. An invagination of the membrane forms a flask-like depression which envelopes the extracellular material.

What is Independent Assortment Bioninja?

Independent assortment describes how pairs of alleles separate independently from one another during gamete formation. According to independent assortment, the inheritance of one gene/trait is independent to the inheritance of any other gene/trait.

What is a bivalent Bioninja?

During prophase I of meiosis, homologous chromosomes become connected in a process known as synapsis. The connected homologues are known as a bivalent (bi = two chromosomes) or a tetrad (tetra = four chromatids) The chromosomes are connected by a protein-RNA complex called the synaptonemal complex.

What is continuous variation Bioninja?

• Continuous variation across a geographical range of related populations matches the concept of gradual divergence. Within a population of any given species there will be genetic variation (i.e. variation which is inheritable)