Chapter 6:DNA structure and replication Flashcards

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1
Q

What does DNA stand for?

A

Deoxyribonucleic Acid

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2
Q

What is a gene?

A

Genetic material is carried and stored in coded in genes, one section of DNA and can be switched off on and by other genes

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3
Q

What does expressed mean?

A

A gene switched on

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4
Q

Where is DNA found in Eukaryotes?

A

Nucleus, chloroplasts and mitochondria

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5
Q

What is chromatin?

A

DNA in a non-dividing cell which only appears grainy and undefined under a microscope

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6
Q

What happens to chromatin when a cell prepares to divide?

A

Condenses by coiling up and thickens allowing individual chromosomes to be seen

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7
Q

What is a chromosome?

A

One molecule of DNA with its associated proteins

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8
Q

How is DNA displayed?

A

Double stranded molecule

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9
Q

What is an unduplicated chromosome?

A

A long double helix molecule coiled around a histone protein

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10
Q

What is a histone?

A

A protein that DNA winds around in eukaryotic cells

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11
Q

What are sister chromatids?

A

Two identical copies of a single chromosomes, formed by replication and connected by centromere

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12
Q

What is a centromere?

A

A waist like construction in a chromosome required for the movement of chromosomes during cell division

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13
Q

What shape do sister chromatids and centromeres form?

A

X shape

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14
Q

When are chromosomes visible?

A

Prior to division stage and after replication has occurred

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15
Q

What are homologous chromosomes?

A

pair of chromosomes that have the same size, shape and genes at the same location

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16
Q

Where do the chromosomes come from in homologous chromosomes pairs?

A

One is inherited from each parent

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17
Q

What is karyotype?

A

The display of the number and appearance of the chromosomes of organisms or observed in metaphase

18
Q

How many pairs of chromosomes do humans have?

A

23 pairs (46 chromosomes)

19
Q

What is the endosymbiotic theory?

A

A theory that suggests chloroplast and mitochondria arose from ancient prokaryote cells that were ingested by other prokaryote host cells

20
Q

What is maternal inheritance?

A

Inheritance only from mothers; any trait that is encoded by organelle DNA only from mother

21
Q

What is a nucleoid?

A

The region within a prokaryotic cell that contains the genetic material.

22
Q

Where are chromosomes join in prokaryotic cells?

A

A single circular chromosome which lies within the cytoplasm. Chromosomes often join to plasma membrane.

23
Q

What is plasmid?

A

A small circular piece of DNA found in bacteria which can replicate independently of the cell’s chromosomes

24
Q

What is a nucleotide?

A

The basic building block of nucleic acids linked by phosphodiester bonds

25
Q

What are nucleotides made of?

A

five-carbon sugar, a phosphate group and nitrogenous base.

26
Q

What are the 4 kinds of nitrogenous bases in DNA?

A

Adenine, thymine, guanine and cytosine

27
Q

What is complementary bases?

A

The nitrogenous bases on nucleotide that bind to each other

28
Q

What are complementary bases that bind?

A

A to T and C to G

29
Q

What holds the double helix together?

A

Hydrogen bonds

30
Q

What does antiparrell mean and do double helix have it?

A

Yes, it means they run the opposite ways

31
Q

How is RNA different to DNA?

A

RNA is a single strand chain of nucleotides, thymine is replaced by base uracil and ribs sugar replaces deoxyribose of DNA

32
Q

How is RNA useful?

A

It is useful in protein synthesis

33
Q

Why does DNA replicate?

A

Growth, repairs and reproduction

34
Q

What is a daughter cell?

A

Either of the two cells formed during cell division

35
Q

What is the start of cell division?

A

The enzyme helicase which helps the double helix unwind by breaking the hydrogen bonds and separate

36
Q

How does Helicase unwind and separate the strands?

A

By breaking the hydrogen bonds exposing the nucleotide bases

37
Q

What is parental DNA?

A

The DNA of the original cell

38
Q

What happens during interphase?

A

Active growth, synthesis of DNA and preparation of next division

39
Q

What is a replication fork?

A

The junction between unwound DNA and joined DNA

40
Q

What is DNA polymerase?

A

An enzyme capable of making exact copies of DNA fragments

41
Q

What happens after hydrogen bonds are broken?

A

DNA polymerase attaches the appropriate base pair to expose nucleotide running in a 3 prime to 5 prime

42
Q

What is semiconservative replication?

A

A double helix consisting of a parental strand and daughter stand. Is the outcome during cell division