"Chromosome Variation" Gene Mutation and Other Variations PPT

Description

"Chromosome Variation" Gene Mutation and Other Variations PPT

Part One: Curriculum Standard Requirements

1. Explain the concepts of chromosome group, diploid, polyploid and haploid.

2. Describe the principles and operating procedures of haploid and polyploid breeding.

3. Conduct experiments on changes in plant chromosome number induced by low temperature.

4. Elucidate the types and consequences of chromosomal structural variation.

Literacy requirements

1. Scientific thinking: Improve the ability to summarize by comparing the differences between chromosome groups, diploids, polyploids, and haploids.

2. Scientific exploration: Improve experimental operation capabilities through the "low temperature-induced changes in plant chromosome number" experiment.

Chromosome variation PPT, part 2: text analysis

1. Variation in chromosome number

Basic review · Consolidate the foundation of teaching materials

1. Concept and types of chromosomal variation

(1) Concept: Changes in chromosomes ________ or ________ in the somatic cells or germ cells of an organism.

(2) Types: Chromosome ________ variation and Chromosome ________ variation.

2. Types of chromosome number variation

(1) Increase or decrease in intracellular ______________.

(2) The number of chromosomes in a cell increases exponentially or decreases in sets by __________________.

3. The concept of chromosome group

In the somatic cells of most organisms, chromosomes are paired, that is to say, they contain two sets of non-homologous chromosomes, of which ______________ is called a chromosome set.

4. Diploid

Individuals that develop from ________ and contain two sets of chromosomes in their somatic cells are called diploids. In nature, almost all ________ and more than half of the ________ are diploid.

5. Polyploidy

(1) Polyploidy: An individual who develops from a fertilized egg and whose somatic cells contain the ______________ chromosome set.

(2) Characteristics: The stems are ________, the leaves, fruits and seeds are relatively ________, the contents of nutrients such as sugar and protein are all ________, and there are also shortcomings such as low seed setting rate and late maturity.

(3) Artificial induction (polyploid breeding)

①Method: Treat with ________ or induce with ________, etc.

②Treatment objects: ________ seeds or ________.

③Principle: It can inhibit the formation of ________, causing chromosomes to be unable to move to the poles of the cell, thereby causing the number of chromosomes in the cell to ________.

6.Haploid

(1) Concept: The number of chromosomes in somatic cells is the same as the number of ________ chromosomes of this species.

(2) Examples: ________ bees among bees, haploid crops.

(3) Characteristics: Compared with normal plants, haploid plants grow smaller and are highly sterile.

(4) Application - haploid breeding

①Method

②Advantages: ______________.

Judgment of right and wrong · Correction is easy to be confused and easy to make mistakes

(1) Haploid somatic cells must contain only one chromosome set ()

(2) Individuals with two sets of chromosomes in their somatic cells must be diploid ()

Analysis: Haploid is an individual that develops from gametes and may contain one chromosome set or multiple chromosome sets.

(3) Diploid or polyploid can be obtained by treating haploid once with colchicine ()

(4) In haploid breeding, colchicine can be used to treat germinated seeds or seedlings ()

Analysis: Haploid plants may be highly sterile and unable to form seeds, so in haploid breeding, only colchicine can be used to treat haploid seedlings.

(5) The genotype of the diploid watermelon seedling is Aa, then the tetraploid formed after treatment with colchicine is homozygous ()

Analysis: The tetraploid formed after Aa is treated with colchicine is AAaa, which is heterozygous.

(6) When diploid rice and tetraploid rice are crossed, triploid can be obtained, and the rice panicles and grains become smaller ()

Analysis: Triploids are infertile and cannot obtain grains.

(7) Colchicine can inhibit the formation of spindles, causing centromeres to fail to divide normally during the late stages of mitosis, so cells cannot divide, thus doubling the number of chromosomes in the cell ()

Analysis: The presence or absence of a spindle does not affect the centromere dividing into two.

In conclusion

(1) Individuals developed from gametes are haploid. Haploid does not necessarily contain only one chromosome set. For example, the somatic cells of hexaploid common wheat haploid contain three chromosome sets.

(2) Not all haplotypes are highly sterile. If the number of chromosomes in a haploid somatic cell is an odd number, then when it undergoes meiosis to form gametes, the homologous chromosomes cannot synapse normally, and normal gametes cannot be produced, resulting in a high degree of infertility; if the haploid somatic cells If the number of chromosomes is an even number, the chromosomes can synapse normally during meiosis and may produce normal gametes and be fertile.

(3) Judgment of whether a polyploid is fertile: Look at the number of chromosome sets. If it is an odd number, the polyploid is infertile. Second, look at the origin of the chromosomes. Both autotetraploid and autooctaploid are fertile; some allotetraploid are infertile, such as common wheat (hexaploid) and rye (diploid). Cross, and the resulting allotetraploid is infertile.

2. Changes in chromosome number in plant cells induced by low temperature

Basic review · Consolidate the foundation of teaching materials

1. Experimental principle

Treating plant ____________________ cells with low temperature can inhibit the formation of __________, causing the chromosomes to be pulled to the poles during cell mitosis, causing the cells to be unable to ____________________. As a result, the number of chromosomes in plant cells changes.

2. Experimental procedures and phenomena

(1)Experimental steps

(2) Phenomenon: There are both normal diploid cells and cells with ________ changes in the field of view.

3. Precautions

(1) The cells observed under the microscope are dead, and the change in the number of chromosomes in the cells cannot be observed.

(2) The selected materials can only be cells in the meristematic zone. Cells that cannot undergo cell division will not change the number of chromosomes.

Deepen exploration and solve problems

(1) In this experiment, does the lower the temperature, the more significant the effect?

Tip: No, it must be "appropriately low temperature" to prevent damage to root tip cells caused by too low a temperature.

(2) Have the chromosomes in all cells been doubled at the time of observation?

Tip: No, only a small number of cells achieve "chromosome doubling", and most cells are still diploid.

3. Variations in chromosome structure

Basic review · Consolidate the foundation of teaching materials

1. Type

2. Results

Changes in the structure of chromosomes will cause changes in the genes arranged on the chromosomes ________ or _______________, leading to mutations in ________.

3. Impact on living organisms

Most chromosomal structural variations are _________ to organisms, and some can even lead to death of organisms.

Judgment of right and wrong · Correction is easy to be confused and easy to make mistakes

(1) The exchange of fragments between chromosomes is a variation of chromosome structure ()

Analysis: The exchange of segments between non-homologous chromosomes belongs to chromosome structural variation, while the exchange of segments between homologous chromosomes belongs to genetic recombination.

(2) X-rays can cause genetic mutations and chromosomal mutations ()

(3) Adding a certain segment to the chromosome can increase gene expression levels, which is a beneficial mutation ()

Analysis: Most chromosome structural variations are detrimental to organisms, and some can even lead to the death of organisms.

Apply what you learn ·Expand link examples

1. The picture below shows abnormal chromosome synapsis in mutant heterozygotes observed under a microscope. The type of chromosome structural variation can be identified through the diagram.

2. Among the above types of mutations, _____ and _____ change the number of genes on the chromosome, and _____ and _____ change the __________ of genes on the chromosome.

Chromosome mutation PPT, the third part: practice in class and implement knowledge

1. In Drosophila melanogaster (2n=8), individuals (monosomic, as shown in the figure) missing one punctate chromosome can still survive and reproduce, but they cannot survive if both punctate chromosomes are missing. . When a number of such Drosophila melanogaster monomers mate with each other, the proportion of their offspring that are monomers is

A.1 B.1/2 C.1/3 D.2/3

2. A chromosome set of a certain diploid organism contains 8 chromosomes. Which of the following statements is incorrect?

A. There are 8 chromosomes in the germ cells produced by this organism

B. There are generally 8 forms of chromosomes in the cells of this organism.

C. These 8 chromosomes can form 4 pairs of homologous chromosomes in meiosis

D. These 8 chromosomes contain all the genetic information required for the growth and development of the organism.

3. (2019 Gansu Qingyang No. 1 Middle School Monthly Examination) Which of the following statements about chromosome groups, diploidy and polyploidy is incorrect?

A. A chromosome set does not contain homologous chromosomes

B. Polyploidy is more common in plants than in animals

C. Diploidy can develop from fertilized eggs, and somatic cells contain two sets of chromosomes.

D. The only way to artificially induce polyploidy is to treat germinating seeds or seedlings with colchicine

4. (2019 Anhui Anqing Five Schools Joint Entrance Examination) Certain types of chromosome structure and number variations can be identified by observing cells in the metaphase of mitosis or the meiosis I stage. a, b, c, and d are the pattern diagrams of chromosomal variation during meiosis I of certain organisms. They belong to

A. Chromosome segment loss, individual chromosome gain, chromosome segment gain, triploidy

B. Triploidy, increase in chromosome segments, increase in individual chromosomes, and loss of chromosome segments

C. Increase in individual chromosomes, increase in chromosome segments, triploidy, and loss of chromosome segments

D.Triploidy, loss of chromosome segments, gain of individual chromosomes, gain of chromosome segments

Keywords: Free download of the PPT courseware for high school biology compulsory course II of the People's Education Press, chromosomal variation PPT download, gene mutation and other variations PPT download, .PPT format;

For more information about the "Gene Mutation and Other Variations Chromosome Variations" PPT courseware, please click the Gene Mutation and Other Variations PPT Chromosome Variations PPT tab.

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Update Time: 2024-10-01

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