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50 Cards in this Set
- Front
- Back
what are the three junctions in animal cells
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tight junctions
desmosomes gap junctions |
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what is the purpose of junctions
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joining multicellular tissue
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what do tight junctions do
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bind cells together
prevent fluid leakage |
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what do desmosomes do
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they anchor the cells
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what do gap junctions do
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allow passage of small molecules for communication
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where are tight junctions typically found
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epithelial tissues
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anchoring junctions, appear as thickened patches in the cell membrane region between two cells.
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desmosomes
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what do desmosomes contain
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specialized proteins like keratin
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where are desmosomes found
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epithelium, smooth muscle and other tissues
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what are their functions desmesomes
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anchoring, support, bind cells together, and anchors for fibers in the cytoskeleton
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what do gap junctions allow
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the passage of water and small molecules
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what do gap junctions assist with
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coordinating activities of the adjecent cells
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an example of gap junction coordination and communication
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if a hormone stimulates one cell and activates adjacent cell
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what junctions are in plant cells
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they do not need junctions. their cell wall is rigid and tough
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higher plant cells are interconnected by
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plasmodesmata
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what are plasmodesmata
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tublike structures in plant cells that go through the cell wall and form fluid connections.
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what do plasmodemata allow
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like a gap junction allow the free exchange of small molecules
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what is the primary role of desmosomes
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binding cells together
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which junction aids in the activities of adjacent animal cells
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gap junctions
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A researcher is using adult stem cells and comparing them to other adult cells from the same tissue. Which of the following is a likely finding?
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The cells from the two sources exhibit different patterns of DNA methylation.
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In animals, embryonic stem cells differ from adult stem cells in that
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embryonic stem cells can differentiate into more cell types than adult stem cells.
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In recent times, it has been shown that adult cells can be induced to become pluripotent stem cells (iPS). In order to make this conversion, what has been done to the adult cells?
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A retrovirus is used to introduce four specific regulatory genes.
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what are the receptors that mediate attachment between a cell and tissue or extracellular matrix around them
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integrins
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during the cell cycle what is the cell doing
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continuing to perform its regular functions
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what regular functions is the cell performing while undergoing the cell cycle
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making hormones, passing messages, growing or fighting infectons but it is still preparing for cell division
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what is the first stage of the cell cycle
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G1
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what occurs during G1 phase
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cell grows and duplicates getting ready to prepare the machinery needed to replicate dna
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what is the second stage of the cell cycle
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S phase
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what occurs during the s phase
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synthesis
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what synthesis occurs during the s phase
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the dna molecule in the nucleus is duplicated
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when does the cell enter the other gap stage
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when dna replication is complete
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what is the third stage
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g2 phase
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what is still occuring during the G2 phase
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cell growth and the duplication of the organells
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what is the final stage of the cell cycle
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m phase
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what makes up the interphase
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two gap phases and s phase
G1 s phase G2 |
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which phase do the cells not divide
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interphase
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where do cells spend most their time in what phase
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interphase
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what does each daughter cell need to have
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an exact copy of the complete genome
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When do cells posses the standard diploid number of chromosomes
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G1 phase
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what does each chromosome contain
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one dna molecule
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what phase is each dna molecule copied or replicated
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s phase
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what are the two copies of the dna molecule that has been replicated called
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sister chromatids
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each pair of sister chromatids are joined at the structure called what
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centromere
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during the s phase what is doubled and what stays the same
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the number of dna molecules double to eight but the chromosomes stay at four
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during which phase are both the number of chromosomes and the number of dna molecules remaining constant
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G2
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Which of the following is a function of the S phase in the cell cycle?
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The synthesis of sister chromatids
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The copying of chromosomes occurs during which of the following phases of the cell cycle?
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s phase
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For the first several divisions of early frog embryos, cells proceed directly from the M phase to the S phase and back to M without gaps. Which of the following is likely to be true about dividing cells in early frog embryos?
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The cells get smaller with each generation.
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If an organism normally has 34 chromosomes, how many molecules of DNA should there be in the G1 phase of the cell cycle?
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34
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Which of the following events would cause the cell cycle to arrest?
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Poor nutrient conditions
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