NSCI Test 1

Origins of Life

Characteristics of Life:

1. Highly organized

2. Homeostasis

   Maintaining stable internal conditions despite external changes is essential for survival. For example, humans regulate body temperature, pH, and hydration levels.

3. Able to use energy

4. Respond to stimuli

5. Reproduction

6. Evolution and adaptation

7. Cellular

-(NOTE: Viruses are not cellular, but can be classified as living)

Miller-Urey Experiment

• Demonstrated the possibility of abiotic synthesis of organic compounds, supporting theories of the origin of life on Earth.

Cell Biology

Prokaryotic Cells

• No membrane bound organelles

• Been around the longest

• Reproduce via fission

Eukaryotic Cells

• Membrane-bound organelles

Cell Division

• Cell Theory- “All cells come from pre-existing cells.”

Mitosis

• is the process by which a single cell divides to produce two identical daughter cells, ensuring equal distribution of genetic material.

• replication for replacement

• Daughter cells are structurally and functionally similar to parent

Meiosis

• Sexual reproduction

• Daughters are half and half of each parent cell

• Crossing over

  • Essentially, it allows traits from both parents to mix, leading to variation in the next generation.

• Everyone has 23 PAIRS of chromosomes, 46 TOTAL.

• There can be XXY or XXX, causing people to be “multiple genders” -Klinefelter syndrome

Genetics

Genes

1. No “mixing” of traits

2. genes control each trait

3. Genes are variable

   1. Allelomorph (alleles)

4. Parents contribute equally

5. Recessive and dominant allele

   1. Dominant always expressed

   2. Recessive is masked

6. What you see is not always what you are

   1. Phenotype- What you see

   2. Genotype- What you are

7. Three genetic Combinations

   1. EX: EE, Ee, ee

Mendelian Genetics

• Studies how traits are inherited through generations, emphasizing the roles of dominant and recessive alleles in determining phenotypic traits. Key principles include segregation and independent assortment of alleles during gamete formation.

• Polydactyly

  • The gene for polydactyl is DOMINANT. Then why doesn’t most of the population have it (6 fingers)?

    • This is because just because it is dominant, it doesn’t mean it is more frequent than recessive. It simply means that it will dominate over a recessive gene IF it’s present.

Non-Mendelian Genetics

• Most mutations do nothing

• Incomplete Dominance

  • A mix of two traits.

    • Ex: Red and White mixing to make Pink

• Codominance

  • Both traits present

    • EX: Black and White dog mix to be Black dog with White spots

• Polygenic

  • Multiple genes influence a trait. Such as the color of your skin or hair

Human Genetics

• Sickle Cell Anemia

  • This wouldn’t

• Blood Typing

  • O is the universal donor

  • AB is a universal receiver

• Sex-Linked Traits

  • Determined by genes on sex chromosome X or Y

  • Hemophilia (family tree)

Molecular Genetics

• What do genes produce?

  • Enzymes

• What are genes made of?

  • DNA

• If it’s dominant, it is expressed, but if it’s recessive, it’s masked

• Transcription: The process of synthesizing RNA from a DNA template. It occurs in the nucleus where DNA is transcribed into messenger RNA (mRNA).

• Translation: The process of synthesizing proteins from an mRNA template. It occurs in the cytoplasm where ribosomes read the mRNA sequence to assemble amino acids into a protein.

CRISPR

• CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats) is a revolutionary technology used in genetic engineering. It allows scientists to precisely edit genes by cutting DNA at specific locations, enabling modifications such as adding, deleting, or altering genetic material. The technology is based on a natural defense mechanism in bacteria that helps them fend off viruses. CRISPR has vast applications in fields such as medicine, agriculture, and biotechnology, making it a powerful tool for research and therapeutic interventions.

• Amino Acids needed:

  • Adenine, Guanine, Cytosine, Thymine

  • James Watson, Francis Crick

  • Rosalind Franklin, Maurice Wilkens

• The Human Genome Project was an international research initiative that aimed to map all human genes.

  • Launched in 1990 and completed in 2003.

  • Identified about 20,000-25,000 genes in human DNA.

  • Determined the sequence of 3 billion base pairs in human DNA.

    • Stored genetic information in databases for research and accessibility.

    • Implications for medicine, biology, and genetics, including advancements in understanding diseases and personalized medicine.

  Embryonic Stem Cells:

  • Derived from early-stage embryos (blastocyst stage).

  • Pluripotent, meaning they can differentiate into nearly any cell type in the body.

  • Can be used in regenerative medicine and research.

  • Ethical considerations due to the source of the cells.

• Somatic Stem Cells (Adult Stem Cells):

  • Found in various tissues in adult organisms (e.g., bone marrow, skin).

  • Multipotent, meaning they can differentiate into a limited range of cell types related to their tissue of origin.

  • Involved in tissue repair and maintenance.

  • Generally considered less controversial than embryonic stem cells

Review

• Frequency of traits

• If someone asks you for an average, find the variant

  • Variant: How spread out the data is

• Midwife Toad

  • Force bread in water to see if they developed sandpaper hands, and they did

  • Paul Cameron

• Know these two things about Meiosis

  1. Crossing over, recombination

  2. Independent Assortment

PEOPLE TO KNOW

• Gregor Mendel

  • Mendelian Genetics

• Hugo de Vries

  • Incomplete Dominance

• George Beadle and Edward Tatum

  • x-rays and UV radiation

• Craig Venter

  • Synthetic Life

• Miller-Urey

  • organic compounds could be formed from simple chemicals under conditions thought to resemble those of early Earth.

• Francesco Redi

  • Sealed jar with flies (Spontaneous generation)

• Louis Pasteur

  • Swan neck (Spontaneous Generation)