Answer:
Each species has a specific identifying number of chromosomes. For example, a cat, <em>Felis catus</em>, has 38 chromosomes, while corn, <em>Zea mays</em>, has 20 chromosomes each chromosome carries specific genes that are unique to that chromosome.
Explanation:
Chromosomes vary in shape and number among living beings. For example, the bacterial chromosome is a unique circular molecule, while human beings have 46 lineal chromosomes arranged in pairs (23 pairs). The total number of chromosomes is specific to each species, and it is denoted as the "chromosomic dotation" of the species.
Genes are the hereditable units that transmit the information needed to specify traits, from parents to offspring, generation to generation. Genes are arranged in sequence in the chromosomes. A chromosome might contain hundreds of thousands of genes.
Genes vary in size and shape. They are composed of pairs of bases, and these sequences also vary in number, producing genes of different lengths. In general, genes code for proteins. Proteins create the organism tissues and perform or carry out specific functions in the organisms, controlling almost all processes and chemical reactions.
Each chromosome carries <u>specific</u> genes that code for <u>specific </u>proteins that have <u>specific</u> functions in the organisms. Each chromosome carries information to synthesize different proteins needed to accomplish a certain function. But <u>not all chromosomes carry the same gene sequences</u>. Only homologous chromosomes carry information for the same trait, but even this information is not necessarily the same. They might have the same gene but different alleles.
Answer:
Meiosis and Genetic Variation.
Explanation:
When homologous chromosomes form pairs during prophase I of meiosis I, crossing-over can occur. Crossing-over is the exchange of genetic material between non-sister chromatids of homologous chromosomes. It results in new combinations of genes on each chromosome.
When cells divide during meiosis, homologous chromosomes are randomly distributed during anaphase I, separating and segregating independently of each other. This is called independent assortment. It results in gametes that have unique combinations of chromosomes.
In sexual reproduction, two gametes unite to produce an offspring. But which two of the millions of possible gametes will it be? This is likely to be a matter of chance. It is obviously another source of genetic variation in offspring. This is known as random fertilization.
Answer:
Psychoactive
Explanation:
Psychoactive effects of drugs are capable of changing the mood, awareness and thoughts of the users/consumers.
Psychoactivity of drugs gives rise to change in the information exchanges between the cells of the brain.They are also able to copy the effects and behavior of neurotransmitters. This gives rise to continued dependence and addiction of such drugs.
Example of psychoactive drugs include cocaine, cannabis, alcohol etc
