The larger the cell becomes, the more demands the cell places on its DNA.
In addition, the cell has more trouble moving enough nutrients and wastes across the cell membrane.
Stages of the Cell Cycle
G1 Phase, S Phase, G2 Phase, M Phase
is a period of activity in which cells do most of their growing. During this phase, cells increase in size and synthesize new proteins and organelles.
In which chromosomes are replicated and the synthesis of DNA molecules take place. key proteins associated with the chromosomes are also synthesized. Usually, once a cell enters the S phase and begins the replictaion of its chromosomes, it completes the rest of the cell cycle.
When the DNA replication is completed, the cell enters the G2 phase. G2 is usually the shortest of the 3 phases of interphase. During the G2 phase, many of the organelles and molecules required for cell division are produced. When the events of the G2 phase are completed, the cell is ready to enter the M phase and begin the process of cell division.
When individuals at the upper and lower ends of the curve have higher fitness then individuals near the middles.
Organisms with 2 different alleles for thesame trait.
Usually located near the middle of the chromatid, although some lie near the ends. It is a poinnt on the chromosomes.
2 Sources of Genetic Variation
By introducing mutations.
Crossing over with homologs.
Organisms with 2 identical alleles for a particular trait.
Parts of a duplicated chromosome.
What is the Factor necessary for a new species?
2 populations are separated by geographic barriers such as rivers, mountains or bodies of water.
Meiosis I results in 2 haploid daughter cells, each with half the number of chromosomes as the original cell.
Occurs when 2 populations are capable of interbreeding but have different courtship rituals or other reproductive strategies that involve behavoir.
In which 2 or more species reproduce at different times.
When individuals near the center of the curve have higher fitness than individuals at either end of the curve.
Contains a single set of chromosomes.
Does not show if there is aa dominant allele present.
Sugar id ribose
The decoding of an mRNA message into a polypeptidde chain (protein)
The process in which RNA molecules are produced by copying part of the nucleotide seequence of DNA into a complentary sequence in RNA.
The sister chromatids separate and move toward opposite ends of the cell.
B BB Bb
b Bb bb
What is this?
Meiosis Phases in order
Prophase I, Metaphase I, Anaphase I, Telophase I and Cytokinesis, Prophase II, Metaphase II, Anaphase II, Telophase II and Cytokinesis.
Each chromosome pairs with its corresponding homologous chromosome to form a tetrad.
Spindle fibers attach to the chromosomes.
Telophase I and Cytokinesis
Nuclear membranes form. the cell separates into 2 cells.
From diploid to haploid
Form tetrads for crossing- over.
The chromosomes line up in a similar way to the metaphase stage of mitosis.
Name of stages in Mitosis in order.
Prophase, Metaphase, Anaphase and telophase.
The chromatin condenses into chromosomes, the centrioles separate and a spindle begins to form. The nuclear envelope breaks down.
The chromosomes line up across the center of the cell. Each chromosome is connected to a spindle fiber at its centromere.
2 main stages of cell division
Mitosis and Cytokinesis.
2 tiny structures located in the cytoplasm near the nuclear envelope. They help organize spindle.
The sister chromatids separate into individual chromosome and are moved apart.
A fanlike microtubule structure that helps separate the chromosomes.
Trait which both alleles contribute to the phenotype.
White Flower and Rd flower make pink.
Traits controlled by 2 or more genes.
Skin (so many)
Carry instructions from DNA to the ribosome so that proteins can be produced. (Messenger RNA)
The chromosome gather at opposite ends of the cell and lose their distinct shape. 2 new nuclear envelopes will form.
Will always show becausse it is dominant.
contains 2 sets of chromosomes.
Which along with specific proteins make up the organelle called called the ribosome whose function is to produce proteins. Ribosomal RNA.
which is involved in bringing the correct amino acid into place for a polymerizing protein chain. Transfer RNA.
Codons work when 3 nucleotides are put together to code for amino acids.
What Genes code for creating?
Genes code for creating proteins.
Darwin's theory of Evolution
During his travels, Darwin made numerous observations and collected evidence that led him to propose a revoltionary hypothesis about the way life changes over time.
Evidence Darwin Discovered
Telophase II and Cytokinesis
Meiosis II results in 4 haploid daughter cells. Duplicate chromosomes haven't been separated.
When individuals at 1 end of the curve have higher fitness than individuals in the middle or at the other end.
The fibers pull the homologous chromosomes toward opposite ends of the cell.
What were the first life forms?
single-celled prokaryote- amino acids.
How did organisms react to the slow increase in oxygen levels?
Drove some life forms to etinction while other life forms evolved new, more efficent metabolic pathways that used oxygen for respiration.
What colors were the seas and why?
Early oceans were brown because of the dissolved iron that they contained.
How much of Earth's life forms have become extinct?
process by which studies of organisms come to resemble one another. When adapting inot a similar environment.
Ex. penguins, dolphins and sharks.
The process by which 2 species evolve in response to changes in each other over time.
Ex. Orchids pollen got deeper so the moths beak got longer.
the process by which studies of fossils or of living organisms show that a single species or a small group of species has evolved, through natural selection and other processes, into diverse forms that live in different ways.
They have selectively permeable membranes through which water molecules can pass. They have simple means of storing and releasing energy.
the age of a fossil is determined by comparing its placement with that of fossil in other layers of rock.
Is the use of half-lives to determine the age of a sample.
Miller and Urey Experiments: What did they demostrate?
Early Earth's Atmospher and building blocks of life which are amino acids.