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Genetics

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Domingo Boyle

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โˆ™ 2021-10-15 18:36:04
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Cards in this guide (27)
What is a chromosome

A chromosome is a threadlike strand of DNA in the cell nucleus that carries the genes in a linear order. It is also known as tightly wound DNA. It is a structure that DNA wraps around.

MORE INFORMATION:

A chromosome is an organized structure of DNA and protein that is found in cells. It is a single piece of coiled DNA containing many genes, regulatory elements and other nucleotide sequences. Chromosomes also contain DNA-bound proteins, which serve to package the DNA and control its functions.

Chromosomes vary widely between different organisms. The DNA molecule may be circular or linear, and can be composed of 10,000 to 1,000,000,000 nucleotides in a long chain.

Cells may contain more than one type of chromosome; for example, mitochondria in most eukaryotes and chloroplasts in plants have their own small chromosomes.

Chromosomes are the essential unit for cellular division and must be replicated, divided, and passed successfully to their daughter cells so as to ensure the genetic diversity and survival of their progeny.

Chromosomal recombination plays a vital role in genetic diversity. If these structures are manipulated incorrectly, through processes known as chromosomal instability and translocation, the cell may undergo mitotic catastrophe and die, or it may aberrantly evade apoptosis leading to the progression of cancer.

In practice "chromosome" is a rather loosely defined term. In prokaryotes and viruses, the term genophore is more appropriate when no chromatin is present. However, a large body of work uses the term chromosome regardless of chromatin content. The simplest genophores are found in viruses: these DNA or RNA molecules are short linear or circular genophores that often lack structural proteins.

Chromosomal DNA encodes most or all of an organism's genetic information; some species also contain plasmids or other extrachromosomal genetic elements.
Structure in nucleus made of DNA and protein. Sections of a chromosomes are genes.
structure in a cell's nucleuse thaat contians genetic material
A chromeosome is organized structure of DNA and protein that is found in cells.
coiled strands of genetic material
coiled strands of genetic material

What is an allele

a form of a gene apex

What are chromosomes

Basically is genetic info.

Different organisms have different types of chromosomes.

In bacteria (prokaryotic cells) a chromosome consists of a loop of DNA; it has no end. Along the length of the DNA are segments called genes, which contain information that the cell uses for growth and development. Most bacteria have only one chromosome, but some have more (the cholera organism Vibrio cholerae has two).

In eukaryotic cells, chromosomes are linear (they have two ends). The DNA is associated with proteins called histones. There is always more than one chromosome in a eukaryotic cell. After cell division and before DNA replication, there is only one molecule of DNA in each chromosome. After DNA replication, there are two DNA molecules in each chromosome; these are separated at the next cell division. In higher organisms, including humans, genes make up only part of the DNA. * * *

A chromosome is a single large macromolecule of DNA, and constitutes a physically organized form of DNA in a cell. It is a very long, continuous piece of DNA. * * * A chromosome refers to the colored thread observed localized within the nucleus. It is the genetic information carrier, and it may be extended (in interphase) or highly condensed (during mitosis or meiosis). The number of chromosomes is species-specific and if any alteration occurs it leads to disease condition or move forward towards evolution. In humans the total number of chromosomes is 46 or 23 pairs; mouse has 44 or 22 pairs; Onion - 16 or 8 pairs; Drosophila - 8 or 4 pairs. A chromosome after DNA replication has a pair of threads called chromatids held together by a primary constriction called a centromere. Chromatids consists of supersolenoid and scaffold structure followed by solenoid structure. Solenoid structure is formed by compaction of polynucleotides bound by histones and non-histone proteins. It leads to a fundamental structure called a nucleosome which consists of a nucleic acid part and a protein part. The protein part consists of positively-charged histones rich in lysine, arginine, and glycine. Histones consists of core subunit made of octamer made of 2 copies of H2A, H2B, H3 and H4. Linker histone H1 connects 2 nucleosomes. Chromosomes are classified based on various criteria: 1) The chromosomes which are common to both males and females are referred to as autosomes or body chromosomes and the chromosomes which determine the sex of an organism are called sex chromosome or allosomes (look dissimilar). In humans we have 22 pairs of autosomes and 1 pair of sex chromosomes (X and Y chromosomes). 2) Classified based on the position of centromere or primary constriction. The either sides of the centromere is referred to as arms (p- petite or short arm; q - quadran or long arm). When p=q (V shaped) - metacentric chromosome; When p<=q (L shaped) - submetacentric chromosome;When p<<< 3) Chromosomes are classified based on the banding pattern. Human chromosomes are classified into 7 groups A - G. A - 1-3; B - 4,5; C - 6-12, X; D - 13-15; E - 16 - 18; F - 19, 20; G - 21, 22, Y. Humans do not have any telocentric chromosomes. He has 5 pairs of acrocentric chromosomes (13 - 15, 21,22).
Chromosomes are structures composed of DNA coiled tightly around proteins called histones. In eukaryotic cells chromosomes are located in the cell nucleus. Chromosomes control the cell's activities and heredity.

What is the role of spindle fibers in mitosis

They pull the sister chromatids apart.

How is cytokinesis different in plants and animals

In plants, a new cell wall forms to split the cell

The allele for tall pea plants is dominate over the allele for short pea plants What must be true for a cross between a tall plant and a short plant to produce any short plants

The thing that must be true for a cross between a tall plant and a short plant to produces any short plants would be that the tall plant would have to be heterozygous. This would mean that fifty percent of the plants would be short.

When is cytokinesis complete

It is complete when two daughter cells are produced. Cytokinesis is the process in which the cytoplasm of a single cell divides to form two daughter cells.

Examples of co-dominance and incomplete dominance

Human blood types are an example of co-dominance, and pink Snapdragons are an example of incomplete dominance.

A species has homologous chromosomes What does this say about the species

A species that has homologous chromosomes is known as a diploid species. Homologous chromosomes are chromosomes that come in identical pairs.Ê

How is the DNA in a prokaryote different from the DNA in a eukaryote

Prokayotes usually have circular DNA, which is found in an area of the cytoplasm called the nucleoid. This, unlike the nucleus of eukaryotes, is not enclosed by a membrane.

Eukaryotes have linear DNA, which is contained within the nucleus of the cell.

Why does meiosis produce cells with half the chromosomes

A gamete needs only half the number of chromosomes because two gametes join together =]

A family has two male children One brother has a straight thumb while the other brother has a bent thumb What causes this difference

The brothers have different alleles.

They received different alleles from their parents

What is true of the allele pair of someone with a genotype TT

The allele pair of someone with a genotype TT is homozygous dominant.

Frederick Griffith made a scientific discovery in 1928 Which best describes the knowledge about genetics before 1928

Scientists did not know how traits were inherited.

In Mendel's experiment why did wrinkled seeds show up in the F2 generation even though they were not present in the F1 generation

Wrinkled seeds are recessive

The F1generation carried recessive alleles.

Dinobryon is a species of protoza that reproduces asexuallyHow is it better for the survival of the species to reproduce asexually instead of sexually

Advantages of Asexual reproduction are as follows:

  • This type of reproduction enable organisms to reproduce without a mate.
  • It does not require the time and energy that takes to search a mate.
  • It results in the reproduction of large number of offspring rapidly.
  • Like in plants, it enables to spread and colonize an area in short period of time.
  • Animals that are confined to one particular place and unable to look for a mate reproduce asexually.
  • Stable environments with very little change are favorable for organisms to reproduce asexually.
What would happen if crossing over didn't happen during meiosis in humans

If crossing over didn't happen during meiosis in humans, the haploid daughter cells would all have the same genes. The crossing over creates variation and causes each daughter cell to have slightly different genes.

What is it called when two forms of traits are both dominant at the same time

Homozygous

How is the DNA in a prokaryote different from the DNA in a eukaryotes

dna in eukaryotes is located in the nucleus

Humans are a diploid species. what does this say about their chromosomes

They have homologous chromosomes

What best describes the the law of independent assortment

The factors for each trait are separated independently when sex cells form.

How is DNA in a prokaryote different from DNA in a eukaryote

DNA prokariyotes is circular. Eukariyotes have linear shape.

How are meiosis and mitosis different

mitosis only has to do with celluar reproduction

meiosis has to do with sex cells reproducing
Mitosis creates new cells that are used for development, repair, asexual reproduction and growth. Meiosis creates cells in order for organisms to reproduce sexually.

A human baby is born with two X chromosomes. What must be true about this baby

Answer this question… A human baby is born with two X chromosomes. What must be true about this baby?

The Arabian spiny mouse is a species of a mouse different mice in this species can have different traits what allows these mice to have different from each other

a

Why did Mendel wanted to find out if the color of the seed of a pea plant affected the seed shape What experiment did he perform to test his idea

He tested seed color and shape at the same time.

APEX

Which is an example of incomplete dominance

(Apex Learning) A white cat and a black cat having grey kittens.

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