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Biology > Chapter 16 > Flashcards

Chapter 16 Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

What is the cell cycle?

A

A series of events that leads to cell division. For eukaryotes, it involves a series of phases in which a cell divides by mitosis or meiosis.

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2
Q

What is cytogenetics?

A

The field of genetics that involves the microscopic examination of chromosomes.

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3
Q

What is a karyotype?

A

A photographic representation of the chromosomes from an actively dividing cell. A karyotype reveals the number, size, and form of chromosomes found within an actively dividing cell.

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4
Q

What are sister chromatids?

A

The two duplicated chromatids that are still joined to each other after DNA replication.

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5
Q

What are sex chromosomes?

A

A distinctive pair of chromosomes that are different in males and females of some species and determine the sex of an individual.

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6
Q

What are autosomes?

A

All of the chromosomes found in the cell nucleus of eukaryotes except for the sex chromosomes. Humans have 22 autosomes.

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7
Q

What are diploid cells?

A

Cells containing two sets of chromosomes; designated as 2n.

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8
Q

What are haploid cells?

A

Cells containing one set of chromosomes; designated as 1n.

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9
Q

What is a homolog?

A

A member of a pair of chromosomes in a diploid organism.

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10
Q

What does homology mean?

A

A similarity that occurs due to descent from a common ancestor.

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11
Q

Are the X and Y chromosomes considered homologous chromosomes?

A

No, X and Y chromosomes differ greatly in size and genetic composition, although they do share some short regions of homology.

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12
Q

Phases of the cell cycle (in order):

A

Interphase, Prophase, Prometaphase, Metaphase, Anaphase, Telophase

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13
Q

Interphase

A

The portion of the cell cycle consisting of the G1, S, and G2 phases, during which the chromosomes are decondensed and found in the nucleus.

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14
Q

What is G0?

A

G0 is a nondividing phase. An alternative to starting G1 in the cell cycle, a cell may postpone cell division, and in some cases it never divides again.

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15
Q

What is mitosis?

A

In eukaryotes, the process in which nuclear division results in two nuclei, each of which receives the same complement of chromosomes.

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16
Q

What is cytokinesis?

A

The division of the cytoplasm to produce two distinct daughter cells.

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17
Q

What factors determine whether or not a cell will divide?

A

External factors include environmental conditions and signaling molecules. Internal factors include cell cycle control molecules and checkpoints.

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18
Q

What is a cyclin?

A

A protein responsible for advancing a cell through the phases of the cell cycle by binding to a cyclin-dependent kinase.

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19
Q

What is cyclin-dependent kinase (cdk)?

A

A protein responsible for advancing a cell through the phases of the cell cycle. Its function is dependent on the binding of a cyclin.

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20
Q

How is cell division regulated during G1?

A

During G1, the amount of a particular cyclin termed G1 cyclin increases in response to sufficient nutrients and growth factors. G1 cyclin binds to cdk. Once activated, cdk functions as a protein kinase that phosphorylates other proteins needed to advance the cell to the next phase in the cell cycle.

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21
Q

What are checkpoints during cell division?

A

One of three critical regulatory points found in the cell cycle of eukaryotic cells. At these checkpoints, a variety of proteins act as sensors to determine if a cell is in the proper condition to divide.

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22
Q

What is a restriction point?

A

A point in the cell cycle in which a cell has become committed to divide. (refers to the G1 checkpoint)

23
Q

What happens if DNA damage is detected during the G1 checkpoint?

A

The checkpoint proteins prevent the formation of active cycline/cdk complexes, thereby stopping the advancement of the cell cycle.

24
Q

What happens during the G2 checkpoint?

A

At this checkpoint, proteins also check DNA for damage and ensure that all of the DNA has been replicated. In addition, the G2 checkpoint proteins monitor the levels of the proteins that are needed to advance through M phase.

25
Q

What is the metaphase checkpoint?

A

Occurs during mitosis and has proteins that monitor the integrity of the spindle apparatus.

26
Q

What is mitotic cell division?

A

A process whereby a eukaryotic cell divides to produce two new cells that are genetically identical to the original cell.

27
Q

What is asexual reproduction?

A

A reproductive strategy that occurs when offspring are produced from a single parent, without the fusion of gametes from two parents. The offspring are therefore clones of the parent.

28
Q

What is a centromere?

A

The region where the two sister chromatids are tightly associated; the centromere is an attachment site for kinetochore proteins.

29
Q

What does kinetochore refer to?

A

A group of proteins that bind to a centromere and are necessary for sorting the chromosomes.

30
Q

What is the mitotic spindle?

A

The structure responsible for organizing and sorting the chromosomes during mitosis; also called the mitotic spindle apparatus.

31
Q

What is a centrosome?

A

A single structure often near the nucleus of a eukaryotic cell that forms a nucleating site for the growth of microtubules; also called a microtubule-organizing center.

32
Q

Where does microtubule growth originate from in animal cells?

A

In animal cells, microtubule growth and organization start at two centrosomes, structures that are also referred to as microtubule-organizing centers.

33
Q

What are centrioles?

A

A pair of structures within the centrosome of animal cells. Most plant cells and many protists lack centrioles.

34
Q

What are the three types of microtubules grow during mitosis?

A

Astral (away from the centrosomes/poles)
Polar (between the two poles)
Kinetochore (microtubules that attach to the kinetochores)

35
Q

What happens during Prophase?

A

The phase of mitosis during which the chromosomes condense and the nuclear membrane begins to vesiculate.

36
Q

What happens during Prometaphase?

A

The phase of mitosis during which the nuclear envelope completely fragments into vesicles and the mitotic spindle is fully formed.

37
Q

What happens during Metaphase?

A

The phase of mitosis during which the chromosomes are aligned in a single row along the metaphase plate.

38
Q

What happens during Anaphase?

A

The phase of mitosis during which the sister chromatids separate from each other and move to opposite poles; the poles themselves also move farther apart.

39
Q

What happens during Telophase?

A

The phase of mitosis during which the chromosomes decondense and the nuclear membrane re-forms.

40
Q

What is a cleavage furrow?

A

In animal cells, an area that constricts like a drawstring to separate the cells during cytokinesis.

41
Q

What is a cell plate?

A

In plant cells, a structure that forms a cell wall between the two daughter cells during cytokinesis.

42
Q

How do prokaryotic cells divide?

A

Binary Fission.

43
Q

What is meiosis?

A

The process by which haploid sex cells are produced from a cell that was originally diploid.

44
Q

What is synapsis?

A

The process of forming a bivalent (Homologous pairs of sister chromatids that are associated with each other, lying side by side) during meiosis I.

45
Q

What is crossing over?

A

The exchange of genetic material between homologous chromosomes during meiosis; allows for increased variation in the genetic information that each parent may pass to the offspring.

46
Q

What is meiosis I?

A

The first division of meiosis in which homologous chromosomes are separated into different cells.

47
Q

During what stage do bivalents form and crossing over occurs between homologous chromosomes?

A

Prophase I

48
Q

What is meiosis II?

A

The second division of meiosis in which sister chromatids are separated into different cells.

49
Q

What is sexual reproduction?

A

A process in which two haploid gametes unite in a fertilization event to produce a cell called a zygote.

50
Q

Why is mitosis important?

A

Mitosis is important to multicellular organisms because it provides new cells for growth and for replacement of worn-out cells, such as skin cells. Many single-celled organisms rely on mitosis as their primary means of asexual reproduction.

51
Q

Why is meiosis important?

A

Meiosis is important because it ensures that all organisms produced via sexual reproduction contain the correct number of chromosomes. Meiosis also produces genetic variation by way of the process of recombination

52
Q

If two chromosomes are homologous, they:

A
  • look similar under the microscope.
  • have very similar DNA sequences.
  • carry the same types of genes.
  • may carry different versions of the same gene.
53
Q

aneuploidy:

A

Alteration of the number of a particular chromosome present in an organism or cell, so the total number of chromosomes is not an exact multiple of a set.

54
Q

polyploid:

A

Refers to an organism or cell that has three or more sets of chromosomes.

Biology (23 decks)

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