bio Flashcards
meiosis
- only happens when producing female/male gametes
- cell divides twice to produce 4 different daughter cells
- all cells haploid (half the # of chromosomes)
- offspring are all genetically different
prophase I: nuclear membrane disappears, DNA condenses and homologous chromosomes start to pair up
metaphase I: homologous chromosomes move together to the middle and line up. crossing over takes place and promotes genetic diversity
anaphase I: chromosomes separate
telophase I: 2 nuclei form, each nucleus contains copy of DNA
prophase II: nuclear membrane disappears, DNA exists as chromosomes
metaphase II: line up in the middle
anaphase II: split to each hole, chromatids split
telophase II:4 nuclei form, cell divides, forming 4 new cells
independent assortment
2 equally probable arrangements of chromosomes in metaphase I that results in 4 different daughter cells
biotechnology and its advantages/disadvantages
the use of technology and organisms to produce useful products. produces useful products. raises ethical problems
cloning
process that produces identical copies of genes, cells or organisms
gene cloning
manipulating DNA to produce multiple copies of a gene or another segment of DNA in foreign cells. Used for further studying or mass producing the protein that the gene codes for.
steps of cloning a gene
1) choose a vector to be used as a carrier of the DNA to be cloned (i.e. plasmid)
- a plasmid is a small, circular piece of DNA in a bacterial cell
2) insert a segment of DNA to clone into the vector
- this DNA molecule that has genetic material from a different source is called recombinant DNA
3) introduce the recombinant DNA into foreign cells through transformation.
- once inside the foreign cells, multiple copies of the cloned gene will be made.
transgenic organisms
organisms that have foreign DNA from a different species inserted into them. We should be concerned because 1) the use of herbicide-resistant plants can lead to the use of stronger herbicides that will leak into the soil and water systems 2) genes can cross to other species 3) GMOs may out-compete species in the wild 4) long-term effects of GMOs are not known 5) GMOs may produce allergic reactions 6) GMO products do not have labels on them 7) a lot of money is spent on genetic research 8) private companies have too much say over the global food market 9) ethics behind using other species for our own benefit.
purposes of transgenic plants and transgenic animals
transgenic plants: increases vitamin intake, reduces malnutrition, increases crop yield and taste. transgenic animals: used to produce human growth hormones or anti clotting factors, may be used as organ donors for humans
artificial insemination
a process that involves collecting and concentrating sperm, and then placing it in the female’s uterus
in vitro fertilization (IVF)
process that results in a female’s eggs being fertilized by sperm outside the body
gene therapy and concerns
an experimental treatment to cure genetic disorders that involve inserting a healthy normal form of a gene into cells of tissues that are affected by a disorder. some people have experienced negative effects with gene therapy, and safer procedures need to be developed.
GMOs
organisms that have foreign DNA from a different species inserted into them.
mutation
permanent change in the genetic material of an organism. they can occur during DNA replication, or as a result of environmental agents such as UV rays, and introduce changes to DNA, resulting in the change of a trait. some mutations can be harmful and cause a cell to die, malfunction, or multiply uncontrollably. some mutations can be positive, or have no effect. E.g. if a bee is mutated so that it has no wings, it’s hard for bees to gather pollen. if bees are given an extra set of legs, it could be helpful. some mutations have no effect on them though.
natural selection
favours traits that make an individual better-suited for its environment, as the population changes since individuals with favourable characteristics survive and reproduce.it’s situational, as a trait that may be a disadvantage to an individual at one time may be advantageous to its survival later.
adaptation
structural or behavioural feature or physiological process that improves the organism’s chance of surviving in its environment to reproduce. it’s important as organisms that have an advantageous mutation may survive better in a changing environment
adaptive radiation
the diversification of a common ancestral species into a variety of differently adapted species. Darwin’s finches are an example because they started off as 1 specie, but due to selective pressure, they broke off into new species
extinction
occurs when a species completely disappears from earth, often due to selective pressure
mutagen
a substance or event that increases the rate of mutation. physical mutagens cause physical changes to the structure of DNA. eg x-rays, UV radiation, chemical mutagens are molecules that can enter the nucleus of a cell and chemically react with DNA. e.g. nitrites, and gas fumes
carcinogen
substance or agent that causes cancer. it increases the risk of developing cancer. e.g. processed foods, cigarettes, cosmetics, bacteria, BBQ, viruses, and cleaning products
artificial selection and benefits and risks
selective pressure exerted by humans on populations in order to improve or modify desirable traits. benefits: we can breed animals that produce more (example: milk), have more meat, and we can breed crops to resist disease, drought and insect infestations. eg/ through selective pressure, the wild mustard plant is used to produce 6 plants. risks: some selectively bred animals have health problems (English bulldogs have respiratory problems). selectively bred plants lack genetic diversity because they are all similar
biodiversity
exists at 3 levels: species diversity, genetic diversity, and ecosystem diversity. species diversity: variety and abundance of species in a given area. genetic diversity: variety of inherited traits within a species. ecosystem diversity: variety of ecosystems in the biosphere. variations in genes is related to all 3 types of biodiversity, as it allows for changes among us. diversity in genes makes us all different.
genetics
field of biology that studies heredity, or the passing of traits from parent to offspring
