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47 Cards in this Set
- Front
- Back
Cells reproduce by ________
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cell division. pg-145
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In cell division a parent cell gives rise to two _________
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daughter cells. pg-145
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In typical cell division, _______
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each daughter cell receives a complex set of hereditary information, usually identical to the hereditary information of the parent cell, and about half of the cytoplasm. pg-145
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The genetic information of all living cells is called ________
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deoxyribosome or DNA. pg-146
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Deoxyribosme or DNA is contained in one or more
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chromosomes. pg-146
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A single molecule of DNA consists of a long chain composed of smaller subunits called
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nucleotides. pg-146
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A single nucleotide consists of a
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phosphate, sugar (deoxyribose), and one of the four bases, adenine(A), Thymine(T), Guanine(G) or Cytosine(C). pg-146
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The units of inheritance are called ________, and are the segments of DNA ranging from a few hundred to many thousands of nucleotides long.
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genes. pg-146
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The structure of DNA
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(a) A nucleotide consists of a phosphate, a sugar, and one of the four bases - adenine(A), thymine(T), guanine(G), or cytosine(C). A single strand of DNA consists of a long chain of nucleotides held together by bonds between the phosphate of one nucleotide and the sugar of the next. (b) Two DNA strands twist around one another from a double helix. pg-146
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The familiar form of cell division in the eukaryotic cells, in which each daughter cell is genetically identical to the parent cell, is called ________
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mitotic cell division. pg-146
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After cell division, the daughter cells may grow and divide again, or they may _________, becoming specialized for specific functions, such as contraction (muscle cells), fighting infections (white blood cells), or producing digestive enzymes (cells of pancreas, stomach, and intestine).
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differentiate. pg-146
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The repeating pattern of divide, grow, and (possibly differentiate), then divide again is called the
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cell cycle. pg-146
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Two important characteristics of stem cells are
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self-renewal and the ability to differentiate into a variety of cell types. pg-146
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Most of the daughter cells formed by the first few cell division of a fertilized egg, and a few cells in adults, including cells in heart, skin, intestine, brain and bone marrow are
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stem cells. pg-146
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Stem cells self-renew because ______________
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they retain the ability to divide. pg-146
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Most of the cells in your heart and brain cannot divide because they are
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permanently differentiated cells. pg-147
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Sexual reproduction in eukaryotic organisms occurs when offspring are produced by the fusion of
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gametes(sperm and eggs) from two adults. pg-147
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Reproduction in which offspring are formed from a single parent, without having a sperm fertilize egg, is called
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asexual reproduction. pg-147
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Paramecium(commonly found in pounds), and Hydra, can both
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reproduce asexually. pg-147
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Both eukaryotic and prokaryotic cells have life cycles that that include,
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growth, metabolic activity, DNA replication, and cell division. pg-148
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What occurs in the prokaryotic cell cycle?
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The DNA of a prokaryotic cell is contained in a single, circular chromosome.
Prokaryotic chromosomes are not contained in a membrane-bound nucleus. Cell replicates it's DNA followed by a type of cell division called binary fission ("splitting in two"). (1). During the growth phase of the prokaryotic cell cycle, the DNA is replicated producing two identical chromosomes that become attached to the plasma membrane. (2). As the cell grows, new plasma membrane is added between the attachment sites of the chromosomes, pushing them apart. (3). When the cell has approximately double in size, the plasma membrane around the middle of the cell grows inward between the two attachment sites. (4). Fusion of the plasma membrane along the equator of the cell completes binary fission, producing two daughter cells, each containing one or more chromosomes. (5). Because DNA replication produces two identical DNA molecules, the two daughter cells are genetically identical to one another and to the parent cell. pg-148 |
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The principal features of a eukaryotic chromosome during cell division.
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(a). Before DNA replication, each chromosome consists of a single DNA double helix. Genes are segments of DNA, usually hundreds to thousands of nucleotides in length. Then ends of chromosomes are protected by telomeres.
(b). The two sister chromatids of duplicated chromosome and are held together by the centromere. (c). The sister chromatids separate during cell division to become two independent, genetically identical chromosomes. pg-150 |
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At the end of DNA replication, a ___________ consists of two identical DNA double helices, now called sister ___________.
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duplicated chromosomes, chromatids pg-150
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Homologous chromosomes, or homologues are __________
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chromosomes that contain the same genes. pg-150
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Cells with pairs of homologous chromosomes are called
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diploid. pg-150
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The changes in the sequence of nucleotides in DNA are called _________, and will make one homologue be a little different genetically, than its pair.
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mutations. pg-151
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A typical human cell has _____ pairs of chromosomes, for a total of _____.
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23, 46 pg-151
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Chromosomes which have similar appearance, similar(but probably not identical) DNA sequences, and are paired in diploid cells of both sexes are called _________.
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autosomes. pg-151
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The cell also has two __________: either two X chromosomes(in females) or an X and a Y chromosome(in males).
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sex chromosomes. pg-151
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Cells that contain only one of each type of chromosome are called ______, and contain one each of the 22 autosomes, plus either an X or Y sex chromosome, for a total of 23 chromosomes.
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haploid. pg-151
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The eukaryotic cell cycle is usually divided into two major phases:
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interphase and (mitotic)cell division. pg-151
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During ______ the cell acquires nutrients from it's environment, grows, and duplicates its chromosome.
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interphase. pg-151/152
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Interphase contains three subphases:
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G1, (the first gap in DNA synthesis and the first growth phase), S (DNA synthesis), and G2 (the second gap in DNA synthesis and the second growth phase). pg-152
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Mitotic and Meiotic are
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two types of cell division in eukaryotic cells. pg-152
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1._________ cell division consists of nuclear division called (2._________) followed by cytoplasmic division called (3.__________).
It takes place in all types of eukaryotic organisms. It is the mechanism of asexual reproduction in eukaryotic cells. It allows organism to maintain its tissue. It is the mechanism whereby stem cell reproduce. |
1.Mitotic
2.Mitosis 3.Cytokinesis pg-152 |
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1.______ cell division is a prerequisite for sexual reproduction in all eukaryotic organisms.
In animals, it occurs only in ovaries and testes. It process involves a specialized nuclear division called 2.________ and two rounds of cytokinesis to produce four daughter cells that can become gametes (eggs and sperm). |
1.Meiotic
2.Meiosis pg-152 |
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1._______ is the first phase of mitosis. During this phase three major events occur: (1). _____________, (2). ___________, and (3). _____________.
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1.prophase
1. The duplicated chromosomes condense, 2. the spindle microtubules form, and 3. the chromosomes are captured by the spindle microtubules. pg-153 |
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Growth factors stimulate cell division.
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Progress through the cell cycle is under overall controll of cyclin and cyclin-dependent kinases(Cdks). In most cases, growth factors stimulate synthesis of cyclin proteins, which activate Cdks, starting a cascade of events that lead to DNA replication and cell division. pg-158
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Progression through the cell cycle is regulated primarily by two interacting processes:
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(1). production of, and responses to, growth factors that generally speed up the cell cycle; and (2). intracellular checkpoints that stop the cell if problems such as mutation in DNA or misalignment of chromosomes have occurred.
Most cancers develop because one or both of these processes goes awry. pg-160 |
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Any gene whose protein product tends to promote mitotic cell division is called ___________.
It is also the gene for growth factors, growth factor receptors, and some of the cyclins and Cdks are __________. It is also essential to the normal control of the cell cycle. |
proto-oncogene. pg-160
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Meiosis (Greek word meaning "diminish")
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reduces the number of chromosomes in a diploid cell by half. pg-162
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During Meiosis
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the cell undergoes one round of DNA replication followed by two nuclear divisions.
One round of DNA replication produces two chromatids in each duplicated chromosome. pg-162 |
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Meiosis halves the number of chromosomes
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(a). Both members of a pair of homologous chromosomes are replicated prior to meiosis. (b). During meiosis I, each daughter cell receives one member of each pair of homologues. (c). During meiosis II, sister chromosomes, and each daughter cell receives one of three chromosomes. pg-163
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Meiotic cell division is essential for sexual reproduction.
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In sexual reproduction specialized reproductive cells undergo meiosis to produce haploid cells. In animals, these cells become gametes (sperm and eggs). When an egg is fertilized by a sperm, the resulting fertilized egg, or zygote, is one again diploid. pg-162
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Haploid life cycle
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meiosis usually occurs soon after fertilization.
Most fungi and unicellular algae spend most of their time in the haploid life cycle. pg-167 |
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Diploid life cycle
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meiosis usually occurs just before fertilization.
Virtually the entire animal life cycle is spent in diploid life cycle. pg-167 |
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Alternation of generations life cycle (plants)
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meiosis occurs at the transition between diploid and haploid. pg-167
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