final Flashcards
What are the parts of the cell cycle?
1) Interphase
2) Cell Division
What happens during interphase?
This is where the cells spend the most time and perform their normal function or job: Gap 1, S phase, and Gap 2
Gap 1
Cell growth
S phase
DNA replication
Gap 2
Cell growth and preparation for division
What happens during cell division (m phase)
Mitosis, cytokinesis
What are sister chromatids?
Identical copies of DNA attached together to make a chromosome
Only exist after DNA replication after S phase
What is a centromere
The middle of a replicated chromosome
What is a telomere
The ends of the chromosomes
Prophase
DNA condenses into chromosomes
Centrioles moves to the opposite “poles” of the cells and send out spindle fibers
Nuclear envelope breaks down and nucleolus disappears
Metaphase
All the chromosomes are lined up across the equator (center) of the cell
Spindle fibers attach to the centromeres of the chromosomes
Each sister chromatid is attached to a spindle fiber originating from opposite poles
Anaphase
Sister chromatids break apart and are now called daughter chromosomes
Daughter chromosomes are pulled to opposite poles of the cell by spindle fibers
Spindle fibers that aren’t attached to chromosomes elongate the cell
Telophase
Chromosomes arrive at opposite poles of the cell and begin to decondense
Nuclear envelope begins to reform and spindle fibers break down
What is cytokinesis
Cell splitting
What is meiosis
Cell division that produce daughter cells called gametes
What is the product of meiosis
4 haploid cells (half the chromosomes)
Also a possibility of swapping of genetic material between homologous pairs
Random alignment in meiosis
Chromosomes line up at the equator randomly, meaning that the chromosomes from mom and dad can be mixed up in the gametes
What is the genotype
The genetic makeup of an organism (alleles)
What is the phenotype
An observable trait (visual appearance)
Dominant vs recessive
An allele can be either dominant or recessive
What is a dihybrid cross
Two trait cross
Filled out by determining the gametes of both parents using the foil method
What is incomplete dominance
Neither allele is dominant over the other
Offspring’s appearance is a blend between the phenotypes of the 2 parents
What is codomiance
Neither allele is dominant over the other
Both alleles are expressed at the same time and a mixture is observed
What is multiple allelism
More than 2 alleles possible for a given gene
Blood types
A, B, AB, or O
Two blood types can be dominant in order to make a combination of co-dominant blood types
Universal Receiver
AB
Universal Donor
O
What are sex-linked genes
Genes that are located on the X chromosome
What are sex-linked traits
Recessive traits, meaning that both x chromosomes must have the gene in order for the trait to be expressed
What do pedigrees do
Study how a trait is passed from one generation to the next
What is the structure of DNA
Two antiparallel strands running in opposite directions held together by hydrogen bonds and nucleotides held together by covalent bonds
What are the nucleotides in DNA
5-carbon sugar called deoxyribose
Phosphate group
Nitrogenous base
What is the base pairing
A and T= 2 hydrogen bonds
G and C= 3 hydrogen bonds
What is the history of DNA
1) Rosalind Franklin used a technique call x-ray diffraction
2) Watson and Crick built models of potential DNA structures and were able to determine it was a double helix
What is the purpose of DNA replication
New copy of DNA for every cell
What does DNA being semiconservative mean
1 parent strand and 1 new strand
Enzymes in DNA replication
Helicase, primase, polymerase, and ligase
Helicase
Breaks hydrogen bonds between strands
Primase
Makes RNA primer
Polymerase
Adds nucleotides to the new strand 5’-3’
Ligase
Creates covalent bonds between nucleotides to connect fragments
What is the leading strand
Strand of DNA being replicated continuously
What is the lagging strand
The strand of new DNA whose direction is opposite to the direction of the growing replication fork
What is transcription
The cell makes mRNA copies of genes that are needed
Where does transcription occur
Nucleus of eukaryotes
Key parts of transcription
mRNA- carriers information from a gene in DNA
RNAP- the enzymes that reads DNA to make mRNA
RNA polymerase- moves along the gene unwinding the DNA and creating a complementary strand of RNA
What is translation
The mRNA is read by the ribosomes to make proteins
Where does translation occur
The cytosol, cytoplasm, or rough ER
Key parts of translation
mRNA- carries information from a gene in DNA
ribosome- binds mRNA and tRNA to link amino acids
tRNA- a type of RNA that matches amino acids to specific sequences of mRNA
Reading the code
Every group of 3 mRNA/DNA bases encodes a single amino acid, called a codon
What are the types of mutations
Insertion- adding one or more nucleotides
Deletion- removing one or more nucleotides
Substitution- changing a single nucleotide for another
Point- Affects only one nucleotide
Effects of mutations
Silent mutation- the nucleotide change still encodes the same amino acid
Missense mutation- replaces the original amino acid with a different amino acid
Nonsense mutation- replaces the original amino acid with a stop codon
Frameshift- caused by the insertion or deletion of a number of nucleotides that is not divisible by 3, this disrupts the reading frame
What is gene regulation
It can change the expression of a gene by turning the gene on or off, down or up
What are activators
Proteins that increase gene expression
What are repressors
Proteins that decrease gene expression
Evidence of evolution
The Earth is old and constantly changing
Populations cannot grow unchecks
Species vary globally, locally, and over time
Charles Darwin vs Jean-Baptiste Lamarck
Descent with modification
Inheritance of acquired traits
Natural selection
Caused by natural forces
Artificial selection
Caused by humans
Process of natural selection
Variations (mutations in genes) in traits exists in populations
Traits that increase fitness are called adaptations
The next generation will have more of the fitter trait
Founder effect
Occurs when a small sample of a larger population establishes a new population
Population bottleneck
When a large population is reduced randomly such as a natural disaster
Biological species concept
A group of individuals that in nature can interbreed and produce fertile offspring but cannot reproduce with members of other species
Prefertilization barriers (prezygotic)
Spatial- separated in space
Behavioral- mating rituals
Mechanical- sex organ incompatibly
Temporal- timing of mating season
Gamete incompatibility- proteins on the egg prevent sperm from binding
Allopatric speciation
Speciation that occurs in different locations
Sympatric speciation
Speciation that occurs in the same location
Biotic vs abiotic
Alive vs not alive
Levels of organization
Species, population, community, ecosystem, biome, biosphere
Population density
How many individuals live in an area (individuals/area)
Population distribuations
Uniform, random, clumped
Exponential growth
Populations have unlimited resources
Logistic growth
Population has limited resources
What are the interactions during symbiosis
Mutualism- both species benefit
Commensalism- one species benefits the other in unaffected
Parasitism- one species benefits the other is negatively affected
Food webs
Show many interconnected paths
Arrows point in the direction of energy flow
Trophic levels
The amount of energy decreases at each level
Each level is only 10% of the previous
Less animals as you move up the food chain
Nutrient cycle
The movement and exchange of key nutrients among biotic and abiotic factors
Pathogens
Anything foreign to the body that causes disease, such as viruses, bacteria, mold, mildew
Innate immunity
Defense that you are born with, They are present all the time and affects many pathogens
Adaptive immunity
Are gained over time as you are exposed to new pathogens. Develops a defense that is specific to the pathogen
Lymphatic system
A series vessels that move through the tissues of the body. It drains, cleans, and returns fluid (lymph) back to the tissues
B cells
Recognize intact antigens that are on the surface of pathogens or circulating freely in body fluids
T cells
Recognize fragments of antigen displayed on the surface of an infected cell
Arteries
Blood vessels that take blood AWAY from the hearts
To the body= oxygenated
From the hearts to the lung= deoxygenated
Veins
Blood vessels that take blood TOWARD the heart
From the body to the heart= deoxygenated
From the lungs to the heart= oxygenated
Types of Animal Respiration
Skin- entire body surface
Gills- extensions of the body surface
Tracheae- Branching internals tubes
Lungs- localized internal organs
