Genetics Hw Chapters 1-3

Suppose that life exists elsewhere in the universe. All life must contain some type of genetic information, but alien genomes might not consist of nucleic acids or have the same features as those found in the genomes of life on Earth. What might be the common features of all genomes, no matter where they exist?

- The ability to replicate the genetic information accurately for the next generation - The ability to store the entire set of information an organism needs for reproduction and development

Gene

-A short segment of a chromosome that codes for an RNA molecule -functional unit of heredity

Which practices in agriculture and animal demonstrate a rudimentary understanding of heredity and genetics?

-Farmers planted seeds from trees that produced the largest, sweetest fruits and not from the trees that produced the smallest or inedible fruits - Primitive societies were more likely to kill wolves that were too aggressive ones as pets and hunting companions -Nomads selected the most muscular cattle for breeding

Which of the statements are reasons why rhinoceroses would be a poor choice as model organisms for studying breast cancer?

-They produce very few offspring at a time and thus require a lot of time to collect meaningful data -They are needlessly large when smaller, more easily handled organisms, such as mice, are available -They are inappropriate for experimental manipulation because they are an endangered species

both cell types

-contain DNA -use ribosomes to synthesize proteins

Order the steps of oogenesis in human females.

-during fetal development, primordial germ cells in the ovaries undergo mitosis to generate diploid oogonia -diploid oogonia continue mitosis and produce primary oocytes before birth -Primary oocytes are arrested at prophase 1 until puberty -the completion of meiosis 1 results in one haploid secondary oocyte and one haploid polar body -secondary oocytes are released in the fallopian tube at ovulation and arrest at metaphase 2 -if fertilized by a sperm cell, the secondary oocyte will complete meiosis 2, generating a fertilized diploid egg and an additional haploid polar body

chromosome

-long DNA molecules visible during mitosis -large genetic element that carries genes essential to cellular function

What are the functions of mitotic cell division?

-organism growth -cell regeneration -asexual reproduction

prokaryotic cells

-relatively small, typically less than 10 micrometers in size -lack a true skeleton

Genotype

-the genetic makeup of an organism -BB

Phenotype

-the physical expression of a gene -freckles

Allele

-variation of a gene -B or b

The fruit fly Drosophila melanogaster has four pairs of chromosomes, whereas the housefly Musca domestica has six pairs of chromosomes. How many different combinations of chromosomes are possible in the gametes of the fruit fly? chromosome combinations in fruit flies:

16

How many different combinations of chromosomes are possible in the gametes of the house fly? chromosome combinations in house flies:

64

Cell theory began to develop in 1839, following the research of Matthias Schleiden and Theodor Schwann into plant and animal tissues. Both the botanist Schleiden and the physiologist Schwann noticed that every organism they viewed under a microscope, whether plant or animal, was composed of cells. Their observations that all living species are made up of one or more cells led to the early formation of cell theory. Which tenet of cell theory is described by the paragraph about the historical observations of cells?

All organisms are composed of one or more cells

What happens during metaphase I of meiosis?

Homologous chromosomes are randomly arranged in the middle of the cell.

Choose the domain of the cell with the best justification.

The cell belongs to Archaea because it has histone proteins, which are present in Archaea and Eukaryota but absent in Eubacteria.

allele

an alternative form of a particular gene

What is the most inclusive definition of a model organism (model system)?

an organism with a biological system that is representative of the same system in other organisms

transmission genetics

analysis of pedigrees to determine the probability of someone inheriting a trait

What are the structures in a cell that group genes together, are composed of chromatin (DNA and protein), and become visible under a light microscope during mitosis?

chromosomes

G2/M checkpoint

detection of DNA damage after replication

spindle assembly checkpoint

ensures that each chromosome is attached to spindle fibers from opposite poles

Based on chromosome number, in which species would you expect to see more genetic variation among the progeny?

house fly

G1/S checkpoint

maintains cell until necessary enzymes for replication are synthesized

Examination of the nucleotide sequences found at the ends of chromosomes

molecular genetics

mechanisms that ensure a high degree of accuracy during DNA replication

molecular genetics

eukaryotic cells

nuclear membrane surrounds DNA

Effect of nonrandom mating on the distribution of genotypes among a group of animals

population genetics

population genetics

study of people on a small island to determine why a genetic form of asthma is so prevalent on the island

What best describes a genome?

the collection of genetic material in an organism

How does the structure of DNA encode genetic information?

the sequence of bases

Study of how the inheritance of traits encoded by genes on sex chromosomes (sex-linked traits) differs from the inheritance of traits encoded by genes on nonsex chromosomes (autosomal traits)

transmission genetics

Cell division by mitosis is a mechanism of asexual cell replication. Some single‑celled organisms reproduce by cell division, and cell division enables multicellular organisms to grow and to repair damaged cells. Which is a product of cell division by mitosis?

two daughter cells with identical chromosomes