DNA and Chromosomes Flashcards

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1
Q

DNA

A

Is a long polymer made of 4 nucleotides

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2
Q

A DNA molecule has two ________ strands of nucleotides

A

Compenmentary

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3
Q

Nucleotides are made up of what?

A

A sugar attached to a phosphate group which makes the sugar -phosphate backbone & also the 4 different types of bases

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4
Q

What are the 4 different types of bases?

A
  1. Adenine (A)
  2. Cytosine (C)
  3. Guanine (G)
  4. Thymine (T)
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5
Q

Nucleotides are the sugar-phosphate & the different types of bases but since the sugar-phosphate backbone is the same & the only thing that changes is _______ we just refer to nucleotides to the _______

A

Bases

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6
Q

Nucleotides(bases) are connected by ________ between the 5’ end of one sugar and the 3’ end of another

A

Phosphodiester Bonds

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7
Q

The end with a hole on the DNA strand is the _________

A

3’ hydroxyl end

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8
Q

The end with a knobe on the DNA strand is the ______

A

5’ phosphate end

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9
Q

________ holds the nucleotides (base-pairs ) together

A

Hydrogen Bonds

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10
Q

A pairs with what base?

A

T & U

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11
Q

C pairs with what base

A

G

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12
Q

The ______ of DNA provides a way for heredity

A

Structure

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13
Q

_______ organize & carry the nucleotide sequences (genetic information)

A

Chromosomes (Main function is to carry genes)

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14
Q

The _________ within a DNA strand encodes the genetic information in an organism (Like a 4 letter alphabet with different messages)

A

Nucleotide sequence

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15
Q

Since genes contains instructions for producing protiens the _________ in DNA must be able to form the amino acid sequence in proteins (Central Dogma)

A

Nucleotide Sequence

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16
Q

Genetic Code

A

The relationship between the nucleotide sequence & the amino acid sequence

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17
Q

In eukaryotic cells DNA is packed into ________ which fits into the nucleus

A

Chromosomes

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18
Q

Eukaryotic DNA is packed into _________

A

Multiple chromosomes (where DNA is disturbed into different chromomses; the human nucleus has 23 different chromomses & 46 all together)

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19
Q

Chromatin

A

The DNA molecule that is folded by proteins in the chromosome

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20
Q

Karyotype

A

An organize display of the full 46 chromosomes in humans

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21
Q

Genes

A

A segment or piece of DNA molecule that contains nucleotide sequence(instructions) to produce certain types of RNA & proteins (Central Dogma)

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22
Q

Genome

A

The total nucleotide sequence(DNA molecules) carried by a complete set of chromosmes in a cell

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23
Q

Junk DNA

A

Additional specific nucleotide sequences required for normal gene expression (Non coding DNA)

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24
Q

______________ are required for DNA replication & chromosome segration

A

Specialized DNA sequences

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25
Q

What two stages occur in the cell cyle ?

A
  1. Interphase
  2. Mitosis
26
Q

Interphase

A

When chromosomes are duplicated

27
Q

Mitosis

A

The duplicated chromosomes are disturbed(segrgated) into the two daughter nuclei)

28
Q

DNA replication occurs in what phase of the cell cycle?

A

Interphase

29
Q

Centromere(Specialized DNA sequence)

A

Allows duplicated chromosomes to be seperated during mitosis phase

30
Q

___________ chromosomes are not randomly distrubted in the nucleus but rather they stay in certain regions in the nucleus

A

Interphase Chromosomes

31
Q

Nucleolus

A

Organization of the interphase chromosomes in the nucleus (Part of the chromosomes containing RNA genes)

32
Q

The DNA in chromosomes are always __________

A

Highly condense (packed tighly & very small)

33
Q

DNA is packed neatly into chromosomes by _________

A

Nucleosomes

34
Q

________ are the basic units of eukaryotic chromosomes structure

A

Nucleosomes

35
Q

What are the two classes of the proteins that fold & bind DNA to form eukaroytic chromosomes?

A
  1. Histone chromosomal proteins
  2. Nonhistones chromosomal proteins
36
Q

_________ are responsible for the formation of nucleosomes

A

Histones

37
Q

Nuclesomomes are the fundamental unit for _________ & convert DNA molecules in an interphase nucleus into a chromatin fiber (small length of DNA & contains clusters of closely packed nucleosomes)

A

Chromosome packagining

38
Q

Nucleosomes contains _____ wrapped around a protein core made up of eight histones

A

DNA

39
Q

Nucleases

A

An enzyme that cut the DNA by breaking the phospodiester bonds between nucleotides

40
Q

The ________ make up the core of the nuclesome

A

Histone protiens (4 of them)

41
Q

The 4 histone proteins that make up the core of the nucleosome have high proportions of ____________ & those positive charges bond tightly to the _______ of DNA

A

Positive charged amino acid, negative charged sugar-phosphate backbone of DNA

42
Q

In living cell _____ are stacked onto each other to make a compact structure

A

Chromatin

43
Q

__________ proteins fold the chromatin into a series of loops which allows chromosmes to become really condensed(tight like the mitotic chromosomes)

A

Nonhistone Chromosomal proteins

44
Q

H1 (type of histone)

A

Pulls adjacent nucleosomes together to stacking on top of each other (It allows it to form a more small condensed chromatin fiber)

45
Q

Changes in __________ structure allows acess in DNA

A

Nucleosomes

46
Q

What are the two ways that eukaryotic cells can change nucleosomes structure?

A
  1. Chromatin -remodeling complexes(proteins)
  2. Histone-modifying enzymes
47
Q

Chromatin-remodeling complexes

A

are proteins machines that use the energy of ATP hydroylsis to change the position of the DNA wrapped around the nuclesomome (They can alter the arragnment of the nucleosmes to allow DNA to be more or less accessible)

48
Q

Histone - modifying enzymes

A

Catalyze the reversible chemical modification of histones

49
Q

The tails of the histone are modified by either an ______ or ______ of acetyl, phosphate, or methyl group

A

Addtion or Removal

50
Q

Aceylation (process of adding an acetyl group)

A

Can loosen DNA & histone interactions

51
Q

Histone modifying enzymes ______ or ________ chromatins

A

Condense(shrink) or relax (expand)

52
Q

Interphase chromosomes contain both _______ & __ forms of chromatins

A

Highly condensed & extended forms

53
Q

The alteration made by _________ & _______ affect the structure of interphase chromsomes

A

Chromating packing remodeling complexes & histone modification

54
Q

Since interphase chromatin are packed into specific regions, regions of the chromsomes containing ______ that are actively expresses are more extended

A

Genes

55
Q

Regions of chromosomes that contain silent genes are ______

A

Condensed

56
Q

Heterochromatin

A

The most highly condensed form of interphase chromatin

57
Q

Euchromatin

A

The non-condensed part of the interphase chromatin

58
Q

Barrier DNA sequence

A

Stops the spread of the heterochromatin

59
Q

DNA that fold into heterochromatin dont contain genes because being packaged really tight into heterochromatin genes fail to be _______

A

Expressed

60
Q

________ can silence genes in the X- chromosomes of female mammals (process called X-inactivation)

A

Heterochromatin