Which event takes place during DNA replication?
Replication occurs in three major steps: the opening of the double helix and separation of the DNA strands, the priming of the template strand, and the assembly of the new DNA segment. During separation, the two strands of the DNA double helix uncoil at a specific location called the origin.
Which of the following are involved in DNA replication?
One of the key molecules in DNA replication is the enzyme DNA polymerase. DNA polymerases are responsible for synthesizing DNA: they add nucleotides one by one to the growing DNA chain, incorporating only those that are complementary to the template.
What event begins the process of DNA replication?
DNA replication begins with the unzipping of the double stranded DNA by the enzyme DNA helicase, which breaks hydrogen bonds as it separates the strands. Another enzyme known as topoisomerase holds the two DNA strands apart whilst helicase works.
What are the two main events in the replication of DNA?
How does DNA replication occur? The double helix unwinds. Enzyme breaks the bond between the base pairs. Other DNA bases now enter the nucleus and join with the exposed DNA strand.
Why does DNA replication take place before cell division?
In order for all of the cells in your body to maintain a full genome, each cell must replicate its DNA before it divides so that a full genome can be allotted to each of its offspring cells. If DNA replication did not take place fully, or at all, the offspring cells would be missing some or all of the genome.
Why is DNA replication important before cell division?
Replication is an essential process because, whenever a cell divides, the two new daughter cells must contain the same genetic information, or DNA, as the parent cell. Once the DNA in a cell is replicated, the cell can divide into two cells, each of which has an identical copy of the original DNA.
Why is DNA in nucleus?
In organisms called eukaryotes, DNA is found inside a special area of the cell called the nucleus. Because the cell is very small, and because organisms have many DNA molecules per cell, each DNA molecule must be tightly packaged. This packaged form of the DNA is called a chromosome.
Why is it important that DNA replication is exact?
Why is it is more important for DNA replication to be exact than for transcription or translation to be exact? (1 point) It is more important for DNA replication to be exact than for transcription or translation to be exact because DNA replication produces the master copy which transcription and translation use as the …
What would a chromosome look like after DNA replication?
When fully condensed, replicated chromosomes appear as thick X-shaped structures that are readily observed under the microscope (see figure below). Chromosomes can have 1 or 2 chromatids, depending on whether they have replicated.
How many chromosomes will be present in a cell after DNA replication?
46 chromosomes
How many chromatids does a chromosome have after DNA replication?
two chromatids
What characteristics do two homologous chromosomes share?
Homologous chromosomes are similar, but not identical. One comes from mom and one from dad. They carry genes for the same inherited characteristic, may of which carry different versions of the same gene. Two homologous chromosomes share position of the centromere, type/location of genes, and length/shape.
What is a heterologous chromosome?
A heterologous chromosome is a chromosome that contains different set of genes for a given trait. Homozygous means that the organism has two copies of the same allele for a gene.
What is the same in all parts of homologous chromosomes?
Homologous chromosomes are chromosomes which contain the same genes in the same order along their chromosomal arms. There are two main properties of homologous chromosomes: the length of chromosomal arms and the placement of the centromere.
What do you mean by homologous chromosome?
A pair of chromosomes made up of two homologs. Homologous chromosomes have corresponding DNA sequences and come from separate parents; one homolog comes from the mother and the other comes from the father. Homologous chromosomes line up and synapse during meiosis.
What is an example of a homologous chromosome?
During sexual reproduction, one chromosome in each homologous pair is donated from the mother and the other from the father. In a karyotype, there are 22 pairs of autosomes or non-sex chromosomes and one pair of sex chromosomes. The sex chromosomes in both males (X and Y) and females (X and X) are homologs.
What allele means?
An allele is a variant form of a gene. Some genes have a variety of different forms, which are located at the same position, or genetic locus, on a chromosome. Humans are called diploid organisms because they have two alleles at each genetic locus, with one allele inherited from each parent.
Are all chromosomes connected?
And, each chromosome has a partner, so unless a cell is dividing, the chromosomes are “paired.” Even the pairs of chromosomes differ, although they both have the same genes, there are variations within each gene to produce variation in the trait that the gene encodes.
Which are the two main parts that make up a chromosome?
DNA is coiled around proteins called histones, which provide the structural support. Chromosomes help ensure that DNA is replicated and distributed appropriately during cell division. Each chromosome has a centromere, which divides the chromosome into two sections – the p (short) arm and the q (long) arm.
What is the main difference between Chromatin and Chromosomes?
Chromatin Fibers are Long and thin. They are uncoiled structures found inside the nucleus. Chromosomes are compact, thick and ribbon-like. These are coiled structures seen prominently during cell division.