Genetics Flashcards
What does genotype mean?
The way genes are structured, eg Bb, BB, bb
What does phenotype mean?
How you look, eg brown eyes
Cell Theory
Everything in the universe is made up of cells
Cell membrane function
Controls what comes in and out of the cell
Nucleus function
Directs the cell’s activities
Cell wall function
Protects and supports a plant cell
Centrioles function?
Help the mitotic spindle
Nuclear membrane function
Protects the nucleus
What happens during interphase?
Cell is growing and developing
Copies its DNA and centrioles
Preparing for mitosis
What happens during mitosis?
Prophase: spindle fibers form
Metaphase: chromosomes form an equator in the middle of the cell
Anaphase: centromeres break and chromatids move towards opposite sides of the cell
Telophase: nuclear membranes form around each set of chromosomes
What happens during cytokinesis?
The cell membrane pinches shut and divides the daughter cells
What is the purpose of mitosis?
To grow and develop the organism
What kind of cells are produced in mitosis?
Body cells
How many chromosomes are in each daughter cell after mitosis?
A full set (humans: 46)
What shape is DNA?
Double helix
What are the parts of DNA?
Sides: sugar (deoxyribose) and phosphate molecules
Rungs: adenine, guanine, thymine, and cytosine held together by hydrogen bonds
How do the bases match up?
In pairs
A always bonds with T
G always bonds with C
What does the order of the bases do?
determine the genes
What did Gregor Mendel experiment with?
Pea plants
What did Gregor Mendel do?
He bred tall/short pea plants together
Explain the Mendelian pattern of inheritance.
Controlled by just one gene
Two alleles - one dominant, one recessive
If one of the dominant allele is present, it will appear in the phenotype
Explain the pattern of inheritance controlled by single genes with three or more alleles.
Three or more alleles; can be co-dominant.
Blood type: A & B are co-dominant; blood types can be A, B, AB, or O
Explain traits controlled by many genes.
Eye color
Height
What is a chromosome?
Strands composed of DNA
What is a gene?
A segment of DNA that codes for a specific trait
What is an allele?
A version of a gene
What does heterozygous mean?
Contains two different alleles for a gene
What does homozygous mean?
Two of the same alleles for a trait
What is a dominant allele?
An allele controlling a trait that will always appear
What is a recessive allele?
An allele that will always be hidden by a dominant allele if present
What is a co-dominant allele?
Alleles which will both be expressed in the phenotype because neither is recessive
What is a Punnet Square?
A visual representation of all possible outcomes of a genetic cross with one parent’s alleles on the top and the others on the bottom and the offspring’s potential alleles in the boxes
What does the Chromosome Theory of Inheritance say?
Chromosomes in sex cells carry genes from parents to offspring
Who came up with the Chromosome Theory of Inheritance?
Walter Sutton
What is the purpose of meiosis?
To create sex cells
What kind of cells does meiosis produce?
Sex cells
How many chromosomes are in each daughter cell after meiosis?
Half the number (humans: 23)
How do you read and construct a pedigree?
First row: parent generation Second row on: F1, F2, etc. (filial or child generations) Circle: female Square: male Horizontal line: marriage Vertical/tree-like lines: children Shaded in: has trait Not shaded in: does not have trait Half shaded in: carrier of trait
What is the Theory of Natural Selection?
Evolutionary change comes from adaptation of organisms to their environment over generations to use the most advantageous variations
Who came up with the Theory of Natural Selection?
Charles Darwin after his journey to the Galapagos Islands
How can characteristics of a species change over time?
Over time, variations are introduced into a species. If a variation is helpful, the individuals with the variation are more likely to live on and reproduce than their counterparts without the variation and the variation becomes the norm
Homeostasis - how do organisms maintain constant internal conditions?
Temperature - sweating, shivering, etc.
What is hibernation?
A behavioral adaptation that allows a species to conserve energy in a long, deep sleep so they don’t have to find resources
What is dormancy?
A behavioral adaptation; a period when an organism’s growth and activity stops
What is migration?
A behavioral adaptation during which an organism travels to a secondary area to find resources regularly
What is group behavior?
A behavioral adaptation where a group of same-species organisms works together
What are structural adaptations?
Beak design - best design = best eating
Protective coloration - camouflage
Seed dispersal - spreading seeds far from their parent plant
Pollination - using animals to spread pollen between plants
What is the difference between mutualism, parasitism, and commensalism?
Mutualism: benefits both organisms
Parasitism: benefits one organism and hurts the other
Commensalism: benefits one organism and does not affect the other
What is competition?
The race between two species to secure resources
What is gene therapy?
Using healthy DNA in a vector to heal damaged or mutated DNA
What is cloning?
Creating an exact replica of an organism
What are stem cells?
Undifferentiated cells that can grow to be many types of cells
What are epidemiologists?
Scientists who study diseases and how they spread
