Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Biology Unit 2 > Genetics > Flashcards

Genetics Flashcards

You may prefer our related Brainscape-certified flashcards:
AP® Biology flashcards Biology 101 flashcards
1
Q

What elements are there in Nucleotides?

A

Carbon, Hydrogen, Oxygen, Nitrogen, Phosphate (CHONP)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is the composition of a Nucleotide?

A
  • A negatively charged phosphate group which makes it acidic
  • A pentose sugar called deoxyribose
  • A nitrogenous base.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are the four types of nitrogenous bases/nucleotides?

A
  • (A) Adenine makes Adenosine
  • (C) Cytosine makes Cytidine
  • (G) Guanine makes Guanosine
  • (T) Thymine makes Thymidine
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is the variability in the number of phosphate groups a nucleotide can have?

A

A nucleotide can have 1, 2 or 3 phosphate groups.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Explain Nucleotide Polymerisation.

A

Nucleotides form phosphodiester bonds in a condensation reaction between Carbon 3 of the sugar and an oxygen atom in the phosphate, creating a sugar-phosphate backbone, so the bases can connect with other bases in other nucleotides. The new polymer has a free phosphate group at the 5’ end and a free OH group at the 3’ end

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are the main features of DNA?

A
  • Double stranded; two antiparellel nucleotides alongside each other.
  • Double Helix
  • Bound together by hydrogen bonds between bases forming base pairs.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is DNA made of?

A

Nucleotides

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are complementary base pairs?

A

The only pairing of bases that will bond together. A and T, C and G, etc.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

How does the structure of DNA make it well suited for storing and expressing genetic information?

A
  • The bases are protected on the inside of the molecule, and the molecule is very stable as it is held together by many hydrogen bonds
  • DNA is long and tightly coiled so it can store a lot of information.
  • Two complementary strands means two copies of information, which is useful for repair, copying and error checking.
  • Bases act as a 4 letter alphabet.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Where does DNA replication start?

A

A specific sequence on the DNA molecule called the replication origin.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What enzyme unwinds and separates the two strands of DNA in the process of DNA replication?

A

DNA Helicase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the new DNA in DNA Replication built up from?

A

Free nucleotides that are present in the nucleoplasm that bind to the old strands by complementary base pairing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What enzyme joins the nucleotides that have paired to an old strand together during DNA replication?

A

DNA Polymerase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What kind of bond are nucleotides bound together by in DNA?

A

Phosphodiester bonds, forming the sugar phosphate backbone.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Once DNA Polymerase has formed newly paired nucleotides into another strand, what occurs?

A

Another enzyme winds the old strands with the newly made strands to make two double Helices, which are copies of the original DNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

How was the mechanism of semi-conservative replication proven?(each new strand having one old and one new strand)

A

Density gradient centrifugation.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What are the functions of DNA?

A

To make proteins of a specific shape and function

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What two definitions are there for a gene?

A
  • A gene is an inherited factor that controls a particular characteristic
  • . . . A section of DNA that codes for a particular polypeptide
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is the process of genes controlling characteristics called?

A

Gene expression

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

How many bases are in a codon?

A

3 bases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

How many different combinations of bases can there be in a codon?

A

64

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

How is the sequence of bases important in determining the characteristics of a cell?

A

The sequence of bases determines the sequence of amino acids which determines the shape and function of the protein (which determines the characteristics of the cell)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What are the two types of non coding DNA?

A

Introns and Satellite DNA?

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is another name for coding DNA?

A

Exons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What are introns?

A

Non coding DNA within a gene

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What is satellite DNA?

A

Non coding DNA in between genes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What makes non coding DNA useful if it does not determine characteristics/code for specific proteins?

A
  • Assists in coiling DNA into chromosomes
  • Has a control function, regulating when genes are to be expressed
  • Involved in DNA replication
  • contains unused copies of genes (pseudo genes)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What is the sum of all of the genes in an organism called?

A

A genome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What is a mutation in terms of DNA?

A

A base pairing error that occurs during DNA replication that causes a change in the characteristic of the cell the protein is coded for.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

How does a mutation cause a change in a characteristic of a cell?

A

A base pairing error causes a change in the sequence of amino acids in the polypeptide which changes the primary, secondary and tertiary structure of the protein, changing its function, which causes a change in the function of the cell overall.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

What is an allele?

A

A different version of a gene

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

What is a genotype?

A

A set of genes in our DNA that is responsible for a certain trait or characteristic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

What is a phenotype?

A

The physical expression of the trait the genotype is responsible for

34
Q

What are silent mutations?

A

Mutations that result in no phenotypic effect. They do not change the protein or are not expressed in the cell

35
Q

Given that a DNA molecule is 1m long, how can it fit into the nucleus of a cell?

A

It is cut into shorter lengths and tightly wrapped around histone proteins to form chromatin which replicates and forms chromosomes

36
Q

Why are chromosomes roughly X shaped?

A

Because they contain two replicated copies of DNA.

37
Q

What is one copy of DNA in a chromosome during DNA replication called?

A

A chromatid

38
Q

What is the name of the location where two chromatids are joined to form a chromosome?

A

Centromere

39
Q

How is prokaryotic DNA different to eukaryotic DNA?

A
  • It is much shorter
  • It is a closed loop
  • It is not associated with histone proteins
40
Q

What is a Karyotype?

A

A Karyotype is the number and appearance of chromosomes in the nucleus of a eukaryotic cell.

41
Q

What are homologous pairs of chromosomes?

A

Chromosomes that have the same size shape and banding pattern

42
Q

How many pairs of chromosomes do humans have?

A

23

43
Q

Are male sex chromosomes homologous or non homologous?

A

Non homologous

44
Q

What are non sex chromosomes called?

A

Autosomal

45
Q

Why do we have two copies of each chromosome?

A

We inherit one copy from each parent

46
Q

What does an ideogram represent?

A

The long coiled DNA molecule in one chromosome

47
Q

What does it mean for a gene to be homozygous in terms of chromosomes?

A

Both the paternal and maternal chromosomes have the same allele

48
Q

What does it mean to be heterozygous in terms of chromosomes?

A

The maternal and paternal versions have different alleles of the gene

49
Q

Genes are distributed along the DNA that comprises a chromosome. What is the defined position of a gene called?

A

The locus

50
Q

How are new cells formed in the body?

A

Mitosis

51
Q

What are the four purposes of making new cells through mitosis?

A
  • Growth
  • Replacement
  • Repair
  • Reproduction(Asexual)
52
Q

What are the two main phases of the cell cycle in mitosis?

A

Interphase and the Mitotic Phase

53
Q

Explain Interphase

A

Where the cell grows and does whatever it is meant to do. Can be split into Growth Phase 1 , Synthesis Phase and Growth Phase 2

54
Q

What is Growth phase 1 of interphase?

A

Where cells grow to their original size, genes are expressed and organelles are replicated

55
Q

What is synthesis phase of Interphase?

A

Where DNA and histones are replicated in perpetration for mitosis

56
Q

What is the second growth phase in Interphase?

A

Where spindle proteins are synthesised, ready for mitosis

57
Q

What are the four sub stages of the Mitotic stage?

A
  • Prophase
  • Metaphase
  • anaphase
  • telophase
58
Q

Explain the details of Prophase in mitosis

A
  • Chromosomes condense and are visible
  • Centrioles at opposite poles of the cell
  • Nucleolus disappears
59
Q

Explain metaphase in mitosis

A
  • Nuclear envelope disappears
  • chromosomes align along equator of cell
  • Spindle fibres connect the centrioles to the chromosomes
60
Q

Explain anaphase in mitosis

A
  • Centromeres split allowing chromatids to split

- Chromatids move centromere-first to the centrioles, pulled by motor proteins walking along the micro tubule tracks

61
Q

Explain Telophase

A
  • Spindle fibres disperse
  • nuclear envelopes form around both groups of chromatids
  • chromatids uncoil and become too thin to see
62
Q

Explain cytokinesis in mitosis

A
  • A ring of actin filaments forms around the equator of the cell and tightens to form a cleavage furrow which splits the cell (Animals)
  • Vesicles move towards the equator and line up to fuse into two membranes called the cell plate, which a new cell wall is laid down in between (Plants)
63
Q

What occurs after mitosis in a multicellular organism?

A

Cell differentiation; turning on all of the required genes and turning off all the others

64
Q

What is Meiosis?

A

Special cell division in sexually reproducing organisms to make gametes.

65
Q

What is the difference between mitosis and meiosis?

A

There are two divisions instead of one, which results in 4 haploid cells (half number of chromosomes) instead of 2 diploid cells

66
Q

What is the particular way in which the chromosome number is halved in meiosis?

A

Each haploid cell has one of each homologous pair of chromosomes.

67
Q

What is genetic recombination and where is it used?

A

Where chromosomes rearrange to form new combinations of alleles found in meiosis

68
Q

Why is genetic recombination significant for meiosis?

A

It is a major source of genetic variation

69
Q

What are the three types of genetic variation?

A
  • Independent assortment
  • Crossing over
  • Random fertilisation
70
Q

Explain independent assortment and when it happens during the process of meiosis

A

During the first meiosis division, the homologous chromosomes join together to form ‘bivalents’ that line up on the equator, but each bivalent is made up of two maternal and paternal chromosomes that can line up in any order which means the chromosomes will be mixed up in the final gametes

71
Q

Explain ‘crossing over’ in meiosis and how it leads to genetic variation

A

When the bivalent said are formed, bits of one chromosomes are crossed over with the corresponding bits of other chromosome, creating chiasmata, which allows paternal and maternal chromosomes to combine

72
Q

What is a chiasmata?

A

The point at which chromosomes cross over during the forming of bivalent a in the first meiotic division, which involve large multi enzyme complexes to cut and join the DNA. (Can be seen under microscope because it changes the shapes of the chromosomes)

73
Q

What is Random Fertilisation?

A

When two gametes fuse to form a zygote.

74
Q

What is the key aspect of a therapeutically useful antimicrobial agent(antibiotic)?

A

Must be selectively toxic; only targets microbes growing in human tissue and not the human host cells themselves.

75
Q

How can antibiotics be selectively toxic?

A

They inhibit enzymes that are unique to prokaryotic cells, like ribosomes.

76
Q

How does penicillin work?

A

It inhibits an enzyme which is involved in the synthesis of peptidoglycan for bacterial cell walls, killing bacterial cells by osmotic lysis as the cell wall bursts from the higher water potential outside the cell.

77
Q

How do bacteria become resistant to antibiotics?

A

Mutations may occur which change the shape of an active site to bind the antibiotic (like penicillin with penicillinase) or it could alter a ribosome so that streptomycin inhibitors can no longer bind.

78
Q

How does vertical gene transmission lead to antibiotic resistance in bacteria?

A

When a bacteria develops a mutation which makes them resistance to an antibiotic, they asexually reproduce by binary fission, and pass on the resistance to its offspring

79
Q

Explain horizontal gene transmission

A

The transfer of genes between bacteria through conjugation

80
Q

How does bacterial conjugation work?

A

When bacteria join together and transfer DNA in the form of one or more plasmids via cytoplasmic bridges/piluses.

81
Q

What is bacterial multiple resistance?

A

When a resistant strain of bacteria develops resistance to more than one antibiotic due to horizontal gene transmission

Biology Unit 2 (4 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions