Biology by breonna

Biology by breonna

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Order to describe the replication of dna in a cell 1. Hydrogen bonds break2. Strands of dna separate 3.free nucleotides are attracted to exposed bases on the loose strands of DNA 4. Hydrogen bonds between nucleotides form
What is the role of dna helicase in the replication of DNA Opens the helix
What term refers to loose dna inside the nucleus Chromatin
During what part of the cell cycle is dna condensed into chromosomes Beginning of M
Gap 1 First stage. Cell growth. Replicated organelles. Cell carries out normal functions. Must pass through critical checkpoint.
Synthesis DNA replication phase. A copy of nuclear dna is made
Gap 2 Third stage. Organelle duplication is completed. Just pass through another critical checkpoint
Mitosis Nuclear division. Includes mitosis and cytokinesis
What happens In each circumstance during mitosis Nuclear membrane dissolves. Duplicated DNA condenses around proteins and separates. Forms to new nuclei
What is the term for two new cells Daughter cells
Cytokinesis The cytoplasm is evenly divided between the daughter cells. New cells are genetically identical.
Why are new cells genetically identical The DNA was copied in S phase 1 full copy of DNA goes into each of the daughter cells during mitosis
W Why do prokaryotic cells divide much faster than eukaryotic cells B Because they do not have the membrane bound organelles found in eukaryotic cells
H How fast do cells divide At the rate at which your body needs it
G0 It is a resting phase. They are unlikely to divide but they continue to carry out normal functions
Do skin cells have a long or short G1 stage Short since cells are replaced regularly
What increases more rapidly as a cell grows Volume
Formula for calculating the surface area of a cell Length times with times number of sides
Formula for calculating the volume of a cell L x W x H
Two materials that must be transported insufficient amounts across the cell membrane Sugar and oxygen and CO2 out
What part of the cell generates the demand for nutrients and produces the waste the cytoplasm of the cell membrane Organelles mitochondria for energy production
If a seller got two large what would it fun difficult to accomplish Nutrients and waste exchange
How does the cell solve the problem of going to argg and how does this solve the problem The cell doubles in size pro two divisions so that each daughter cell is about the right size
Describe the X ternal factors include Physical: cell to cell contact when cells touch each other they stop growing Chemical: growth factors trigger cell growth
How do growth factors work They bind to receptors that activate genes
What is a specific example of growth factor discussed in the book and what does it do Erythropoietin: Stimulates production of red blood cells in response to reduce blood oxygen levels
What is the process of programmed cellular death called Apoptosis
What is the effect of the X ternal and internal signals that lead to apoptosis They activate genesthat produce self-destructive enzymes
Describe in apoptosis in human development Webbing is present in human hands and feet in early development
What feature is characteristic of all cancers Uncontrolled cell division
What are the two types of tumors Malignant and benign
Benign Cells remain clustered together
Malignant Cells invade other tissues or break up and move to other parts of the body
What are two features of cancerous cells that make them harmful They do not perform specialized functions. They absorb body nutrients. They put pressure on other organs and systems
What causes normal cells to become cancerous cells Damage to regulatory genes
Cancer cells Carrie mutations in two types of genes Oncogenes: accelerate the cell cycleSecond type of genes: act as cell cycle brakes
Sources of mutation in cancer causing genes include Inherited errors in errors. Exposure to radiation or chemicals
Carcinogens Substances known to produce or promote cancer
Three cancer causing agents Tobacco smoke. Air pollutants. Viruses
What are stages 1 2 & 3 called collectively Interphase
What occurs during interphase Cell growth
M Mitosis and cytokinesis M Make up stage four
What a occurs during stage four Cell division
What is the purpose of the cell cycle Growth and division
Interphase Period of growth. Contains G1 S And G2.
What is chromatin Uncondensed DNA
Mitosis DNA condenses and becomes visible. Now called chromosomes. Nucleolus and nuclear membrane disappear.
Prophase Chromatin condenses into tightly coiled chromosomes. Each contains two identical sister chromatids. This breaks down the nuclear envelope. This disappears nucleolus.
Prophase These begin to move to These begin to move to opposite sides of cell: Centrosomes and centriolesThese form from centrioles Spindle fibers
M Metaphase C Chromosomes line up along center of Cell.. Each held in place by spindle fibers attached to Kinectochotre
Anaphase The two chromatids separate at centromere. Each chromatid now called a chromosome move toward opposite poles. Microtubules pulled into poles and disappear
Telophase Chromosomes uncoil in return to chromatin form. Centrioles and spend a fibers disappear. Nuclear membrane and nucleolus reform
Cytokinesis Cytoplasm and replicated organelles divide in half and form to new identical cells (animals):Pinched and have the cell membrane grows to enclose both cells
Cytokinesis: plants Plants form a cell plate across the middle of the cell a new cell wall then forms on both sides
Describe the contents of a nucleus during interphase DNA is uncondensed in chromatin form
Are a nucleolus and nuclear membrane present in the cell Yes
Are distinct rod shaped structures called chromosomes easily observed in the nucleus at this time No
What term is used to describe nuclear contents during interphase Chromatin
What important event occurred to the genetic information during the stage DNA is replicated
List to other events that occur during interphase to prepare the cell for mytosis Cellular growth and increase in organelles
Prophase Chromosomes are now visible during prophase
The nucleolus is an organelle located in the nucleus and is the site at which ribosomes are synthesized the nucleolus breaks down during the phase describe changes that have occurred to the nuclear membrane and the special structures forming in prophase Nuclear membrane begins to dissolve spindle fibers a symbol and centrioles move toward the polls
Explain why chromosomes canal be observed but wea??re not observable during interphase They have condensed. But coiling up to form chromosomes they have become larger and viewable under a microscope
What is the name for the disc of proteins that serves as a platform for assembling the microtubules and is located at the centromere Kinetochore
Metaphase
Describe where the chromosomes are now located in relation to the cell Kinetochore
Can evidence of chromosomes duplicated now be observed Yes
How many chromosomes are observed in figure 4 Six
What are the fibers call to become visible during metaphase Spindle fibers
These fibers are mostly composed of Microtubules
What term is used to describe the structure I would each fiber attaches to a chromosome Centromere
Anaphase
What is occurring to each chromosome pair duringAnaphase Sister chromatids are pulled towards opposite poles becoming full chromosomes
Toward what area of the cell or sister chromatids being directed The polls
What structure is responsible for the movement of chromosomes during this phase Spindle fibers
Once the centromere divides each sister chromatid is now referred to as a Chromosome
Telophase
How many chromosomes are visible at each Paul in the figure Six
What happens to the appearance of chromosomes during this phase They begin to disappear and decondense
What term will be used to refer to the chromosomes due to their appearance or lack Chromatin
What cell parts begin to reappear doing this phase Nuclear membrane and nucleolus
What cell parts begin to break down Spindle fibers
Cytokinesis
Is cytokinesis part of mitosis No
What divides in half during cytokinesis Cytoplasm
How many cells have now formed from an original cell Two
How does the number of chromosomes found in each daughter cell compared to the number found in the original cell The exact same
Plants are a little different from animals because they must form would between two new cells Cell plate
Which stage requires the longest time for completion mitosis or interphase Interphase
Which phase of mitosis requires the longest time for completion Prophase
Which phase of mitosis requires the least amount of time Anaphase
In normal chicken cells which stage requires the longest time for completion interphase or mitosis Interphase
In normal chicken cells which phase of mitosis requires the longest time for completion Prophase
How do cancer cells differ from normal cells in total time required for my ptosis Shorter time spent in mitosis
How do you cancer cells different from normal cells in time spent for each phase in my ptosis Spin much less time in prophase about the same in metaphase and anaphase in a little less in Telo phase

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