BIOLOGY 152 Lecture Notes - Lecture 8: Sister Chromatids, Dna Replication, Tangled

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carminehedgehog582

14 Nov 2017

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Dna replication: parental strands serve as the templates for the daughter strands. Sister chromatids: a duplicated chromosome consists of two long, tangled filament (sister chromatids) bunched into an x shape. The order in which one base pair follows the next varies a lot among spe(cid:272)ies. ((cid:272)ha(cid:396)gaff"s 2nd rule) Va(cid:396)iatio(cid:374)s i(cid:374) (cid:271)ase se(cid:395)ue(cid:374)(cid:272)e a(cid:396)e the sou(cid:396)(cid:272)e of life"s di(cid:448)ersity. The order of nucleotide bases in a strand of dna- the dna sequence is genectic info. Descendant cells must get an exact copy of dna. When the cell reproduces, it must contain 2 sets of chromosomes, 1 for each of its future offspring. Dna duplicates itself by dna replication: the two strands of a dna molecule are complementary: nucleotides match up according to base-pairing rules (g to c, and t to a) Dna helicase breaks the hydrogen bonds that hold the double helix together, and the two dna strands unwind.

Related Questions

5- Somatic ("body") cells are _______________ (2n). This means there are two copies of each chromosome.

6- During the _______ phase(s) cells perform their everyday functions.

7- When chromosomes are duplicated the two strands are called _______________________________ and they are linked together at a point called the ____________________.

sister strands; kinetochore

sister chromatids; centromere

dual chromatids; centromere

genes; chromatid

8- New somatic âbodyâ cells are formed by this process:

meiosis

binary fission

replication

mitosis

9- The cytoplasmic division of a cell at the end of mitosis or meiosis, bringing about the separation into two daughter cells.

10- Cells replicate their DNA during ________________ phase.

byzantiumlion207

1- Most of a cell's life is spend in this phase of the cell cycle:

--------------------

2- The cell cycle is a highly regulated process.

True

False

3- Cells replicate their DNA during ________________ phase.

4- In animal cells, ________________________ is the indentation of the cell's surface that marks cytokinesis, the final splitting of the membrane, in the process of cell division.

cleavage furrow

binary fission

cell plate

sister chromatids

5- Somatic ("body") cells are _______________ (2n). This means there are two copies of each chromosome.

6- During the _______ phase(s) cells perform their everyday functions.

7- When chromosomes are duplicated the two strands are called _______________________________ and they are linked together at a point called the ____________________.

sister strands; kinetochore

sister chromatids; centromere

dual chromatids; centromere

genes; chromatid

8- New somatic âbodyâ cells are formed by this process:

meiosis

binary fission

replication

mitosis

9- The cytoplasmic division of a cell at the end of mitosis or meiosis, bringing about the separation into two daughter cells.

10- Cells replicate their DNA during ________________ phase.

pucecat917

1). Explain the significance of the fact that gametes contain half of the chromosome complement of somatic cells. Tell me something about variation, if you have a sibling (if you don't imagine you do) - how is your sibling's genetic make-up similar and/or different from yours? What about your mom and dad?

2). Explain the terms reductional division and equational division. What is reduced or kept equal? To which nuclear divisions do these terms refer?

3). What is the diploid number (2n = ?) of an organism if it has
a) 12 chromosomes at Anaphase of Mitosis?
b) 12 chromosomes at Anaphase I of Meiosis?
c) 12 chromosomes at Anaphase II of Meiosis?

4). Compare/contrast Metaphase I of Meiosis with Metaphase of Mitosis.

5). What are the two mechanisms of variation in Meiosis, and during which stage(s) does each occur?

6). Draw a diagram of a bivalent and label the following parts: centromere, sister chromatids, non-sister chromatids, homologous chromosomes, chiasma.

7). A diploid cell has 1 pair of acrocentric chromosomes (Chromosome 1) and 1 pair of submetacentric chromosomes (Chromosome 2).
Â· Gene X is on Chromosome 1. Gene Y is on the short arm of Chromosome 2 and Gene Z is on the long arm of Chromosome 2.
Â· The maternal chromosomes have the X, y, z alleles, whereas the paternal chromosomes have the x, Y, Z alleles.
Draw these chromosomes, labeling ALL alleles, as they might appear in Metaphase I of Meiosis.

BIOLOGY 152 Lecture Notes - Lecture 8: Sister Chromatids, Dna Replication, Tangled

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