Science - 2018-19

BIO.5 a-d, f, i-j - Cell Growth & Heredity

The student will investigate and understand common mechanisms of inheritance and protein synthesis. Key concepts include
a) cell growth and division;
b) gamete formation;

c) cell specialization;

d) prediction of inheritance of traits based on the Mendelian laws of heredity;
f) genetic variation;
i) use, limitations, and misuse of genetic information;
j) exploration of the impact of DNA technologies.

Bloom's Levels:  Analyze; Understand

Adopted: 2010

BIG IDEAS

  • All living things reproduce to produce more of their own kind.
  • All cells come from other cells.
  • Genetic information is passed from generation to generation by DNA; DNA controls the traits of an organism.

  • I can explain how tumors grow.
  • I can explain why different organs perform different tasks.
  • I can justify why I look like others in my family.
  • I can explain why some populations have gone extinct or have significant developmental issues.
  • I can use my DNA to predict what diseases I may have later in life.

UNDERSTANDING THE STANDARD

  • All living cells come from other living cells. A typical cell goes through a process of growth, development, and reproduction called the cell cycle. 
  • The many body cells of an organism can be specialized to perform different functions, even though they are all descended from a single cell and contain essentially the same genetic information.
  • Mitosis produces two genetically identical cells. During mitosis, the nucleus of the cell divides, forming two nuclei with identical genetic information. Mitosis is referred to in the following stages: prophase, metaphase, anaphase, and telophase. 
  • Many organisms are capable of combining genetic information from two parents to produce offspring. Sex cells are produced through meiosis. This allows sexually reproducing organisms to produce genetically differing offspring, and maintain their number of chromosomes. Meiosis occurs in sexual reproduction when a diploid germ cell produces four haploid daughter cells that can mature to become gametes (sperm or egg). 
  • Genetically diverse populations are more likely to survive changing environments. Recombination and mutation provide for genetic diversity. Some new gene combinations have little effect, some can produce organisms that are better suited to their environments, and others can be deleterious.
  • Mitosis and meiosis refer to division of the nuclear material. Cytokinesis is the division of the cytoplasm and organelles. 
  • The many body cells of an organism can be specialized to perform different functions, even though they are all descended from a single cell and contain essentially the same genetic information.

  • Mendel’s laws of heredity are based on his mathematical analysis of observations of patterns of inheritance of traits. Geneticists apply mathematical principles of probability to Mendel’s laws of heredity in order to predict the results of simple genetic crosses. The laws of probability govern simple genetic recombinations. 
  • Genotype describes the genetic make-up of an organism and phenotype describes the organism’s appearance based on its genes. Homozygous individuals have two identical alleles for a particular trait, while heterozygous individuals have contrasting alleles. When one allele masks the effect of another, that allele is called dominant and the other recessive. When an intermediate phenotype occurs and no allele dominates, incomplete dominance results. Many other patterns of inheritance exist including multiple alleles, polygenic inheritance, and sex-linked inheritance.
  • Inserting, deleting, or substituting DNA bases can alter genes. An altered gene may be passed on to every cell that develops from it, causing an altered phenotype. An altered phenotype may be neutral, beneficial or detrimental. Sometimes entire chromosomes can be added or deleted, resulting in a genetic disorder. These abnormalities may be diagnosed using a Karyotype.
  • In order for cells to make proteins, the DNA code must be transcribed (copied) to messenger RNA (mRNA). The mRNA carries the code from the nucleus to the ribosomes in the cytoplasm. RNA is a single-stranded polymer of four nucleotide monomers. A RNA nucleotide is identified by the base it contains: adenine (A), guanine (G), and cytosine (C) or uracil (U). 
  • At the ribosome, amino acids are linked together to form specific proteins. The amino acid sequence is determined by the mRNA molecule. 
  • DNA technologies allow scientists to identify, study, and modify genes. Forensic identification is an example of the application of DNA technology.
  • Genetic engineering techniques are used in a variety of industries, in agriculture, in basic research, and in medicine. There is great benefit in terms of useful products derived through genetic engineering (e.g., human growth hormone, insulin, and pest- and disease-resistant fruits and vegetables). 
  • Eugenics, a pseudo-science of selective procreation, was a movement throughout the twentieth century, worldwide as well as in Virginia, that demonstrated a misuse of the principles of heredity. 
  • The Human Genome Project is a collaborative effort to map the entire gene sequence of organisms. This information may be useful in detection, prevention, and treatment of many genetic diseases. The potential for identifying and altering genomes raises practical and ethical questions. 
  • Cloning is the production of genetically identical cells and/or organisms. 

ESSENTIALS

In order to meet this standard, it is expected that students will

a) create a diagram to model the stages of mitosis and explain the processes occurring at each stage.

     compare and contrast the process of mitosis and meiosis and determine under which conditions each process will occur.

b) create a diagram to model the stages of meiosis and explain the processes occurring at each stage.

c) describe the importance of cell specialization in the development of multicellular organisms.

d) explain how the Mendelian laws of heredity apply to the patterns of inheritance.

     identify the traits expressed from a given genotype.

     use a Punnett square to show all possible combinations of gametes and the likelihood that particular combinations will occur in monohybrid and dihybrid crosses.

f) evaluate karyotype charts and make a determination of the genderand genetic health of the individual.

     provide examples of reasons for genetic  diversity and why it can be an advantage for populations.

     provide examples of mutations that are lethal, harmful, and beneficial.

i) evaluate examples of genetic engineering and the potential for controversy.

     describe the uses, limitations, and potential for misuse of genetic information.


KEY VOCABULARY

gene, gene expression, genetic predisposition, dominant, recessive, chromosome, haploid, diploid, allele, phenotype, genotype, trait, homozygous, heterozygous, mutation, albino, inheritance, test cross, inversion, drosophila, pedigree, sex-linked, fertility, pollinator, reproduction, fertilization, embryo, zygote, asexual, gamete, development

Updated: Dec 01, 2017