Brainscape's Knowledge GenomeTM

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


See full index

Biology > 8 Gene expression: 20 Gene Expression > Flashcards

8 Gene expression: 20 Gene Expression Flashcards

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

When may gene mutations arise?

A

Spontaneously, during DNA replication.

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

What are the different types of gene mutation?

A

Addition, deletion, substitution, inversion, duplication, and translocation of bases.

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

What is base addition?

A

One or more bases are added.

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

What is base deletion?

A

One or more bases are removed.

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

What is base substitution?

A

One or more bases are swapped for another.

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

What is base inversion?

A

A sequence of bases is reversed.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is base translocation?

A

A sequence of bases is moved from one location in the genome to another.

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

What is mutation rate increased by?

A

Mutagenic agents.

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

What can mutations result in?

A

A different amino acid sequence in the encoded polypeptide.

Due to the degenerate nature of the genetic code, not all mutations result in a change to the encoded amino acid.

Some gene mutations change the nature of all base triplets downstream (frame shift).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What can totipotent cells do?

A

Divide and produce any type of body cell.

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

How do totipotent cells specialise?

A

During development, totipotent cells only translate part of their DNA.

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

When do totipotent cells occur?

A

For a limited time, in early mammalian embryos.

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

Where are pluripotent cells found?

A

Embryos.

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

What can pluripotent cells differentiate into?

A

Any cell in the body, but the cells that make up the placenta.

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

What can multipotent stem cells differentiate into?

A

A few different types of cell.

e.g. red and white blood cells can be formed by multipotent cells in the bone marrow.

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

What can unipotent stem cells differentiate into?

A

One type of cell.

e.g. one type can only differentiate into epidermal skin cells.

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

Which stem cells are present in mature mammals?

A

Multipotent and unipotent stem cells.

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

How can pluripotent stem cells be used to treat leukaemia?

A

Bone marrow transplants can be used to replace faulty bone marrow.
The stem cells in the transplanted bone marrow divide and specialise to produce healthy blood cells.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

How can pluripotent stem cells be used to treat spinal cord injuries?

A

Stem cells could be used to replace damaged nerve tissue.

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

How can pluripotent stem cells be used to treat heart disease and damage caused by heart attacks?

A

Stem cells could be used to replace damaged heart tissue.

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

How can pluripotent stem cells be used to treat bladder conditions?

A

Stem cells could be used to grow whole bladders, which are then implanted in patients to replace diseased ones.

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

How can pluripotent stem cells be used to treat respiratory diseases?

A

Donated windpipes can be stripped down to their simple collagen structure and then covered with tissue generated by stem cells. This can then be transplanted into patients.

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

How can pluripotent stem cells be used to treat organ transplants?

A

Organs could be grown from stem cells to provide new organs for people on donor waiting lists.

24
Q

How are cardiomyocytes made from unipotent stem cells?

A

There is a small supply of unipotent stem cells in the heart which replace old/ damaged cardiomyocytes.

25
Q

What are cardiomyocytes?

A

Heart muscle cells.

26
Q

What are the benefits of using stem cells in medicine?

A

They could save many lives, and improve quality of life.

27
Q

How are induced pluripotent stem cells (iPS cells) produced?

A
  1. Adult body cells are made to express a series of transcription factors that are associated with pluripotent stem cells.
  2. The transcription factors cause the adult cells to express genes that are associated with pluripotency.
  3. This can be done by infecting adult cells with a specially-modified virus. The virus has the genes coding for the transcription factors within its DNA. When the virus infects the adult cell, the genes are passed into the adult cell’s DNA, so the cell is able to produce the transcription factors.
28
Q

What is the main disadvantage to using adult stem cells?

A

They’re multipotent so can only specialise into a limited range of cells.

29
Q

What are the ethical issues surrounding the use of embryonic stem cells?

A
  • involves the destruction of an embryo that could become a fetus
  • some believe embroys have a right to life
30
Q

How can transcription of target genes be stimulated/ inhibited in eukaryotes?

In general

A

When specific transcriptional factors move from the cytoplasm into the nucleus.

31
Q

How do transcription factors work?

A
  1. Transcription factors move from the cytoplasm into the nucleus.
  2. They bind to specific DNA sites near the start of their target genes.
  3. Some transcription factors (activators) stimulate/ increase the rate of transcription by helping RNA polymerase bind to the start of target gene and initiating transcription.
  4. Some transcription factors (repressors) inhibit/ decrease the rate of transcription by preventing RNA polymerase from binding.
32
Q

What is the role of oestrogen in initiating transcription?

A
  1. Oestrogen binds to a transcription factor - an oestrogen receptor, forming an oestrogen-oestrogen receptor complex.
  2. The complex moves from the cytoplasm into the nucleus, where it binds to specific DNA sites near the start of the target gene.
  3. The complex acts as an activator of transcription, helping RNA polymerase bind to the start of the target gene.
  4. In some cells, the oestrogen-oestrogen receptor complex can repress transciption instead.
33
Q

What does epigenetic control determine?

A

Whether a gene is expressed or not.

34
Q

What does epigenetics involve?

A

Heritable changes in gene function, without changes to the base sequence of DNA.

Changes caused by the environment, involving increased methylation of DNA and decreased acetylation of histones.

35
Q

What does increased methylation of DNA do?

A

Increased methylation of the DNA coding for a specific gene changes the DNA structure so that transcriptional machinery (e.g. transcription factors) can’t bind to the gene - the gene isn’t expressed.

36
Q

What does increased acetylation of histones do?

A

When histones are acetylated, the chromatin is less condensed so transcriptional machinery (e.g. transcription factors) can access the DNA and transcribe the genes.

37
Q

What does decreased acetylation of histones do?

A

When acetyl groups are removed from histones, the chromatin becomes highly condensed so transcriptional machinery (e.g. transcription factors) can’t access the DNA to transcribe genes.

38
Q

What enzyme is responsible for removing acetyl groups from histones?

A

Histone deacetylase (HDAC) enzymes.

39
Q

What is the relevance of epigenetics in treating diseases?

A

Drugs can be designed to counteract epigenetic changes that cause disease.

e.g. drugs that stop DNA methylation and inhibit histone deacetylase activity.

40
Q

How can cancer be treated, relevant to epigenetics?

A

Drugs can stop DNA methylation of tumour supressor genes.

41
Q

What is RNA interference?

A

Where small, double stranded RNA molecules stop mRNA from target genes being translated into proteins.

42
Q

What is the process of RNA interference, involving siRNA?

A
  1. mRNA is transcribed and leaves the nucleus.
  2. In the cytoplasm, double-stranded siRNA associates with several proteins and unwinds.
  3. A single strand of siRNA binds to the target mRNA (complementary base pairing).
  4. The proteins with the siRNA cut the mRNA into fragments so it can no longer be translated.
  5. The mRNA fragments are degraded.
43
Q

What is the process of RNA interference, involving miRNA?

A
  1. mRNA is trancribed and leaves the nucleus.
  2. In the cytoplasm, miRNA associates with proteins and binds to the target mRNA. (miRNA isn’t fully complementary to target mRNA so is less specific than siRNA and may target more than one mRNA molecule).
  3. The miRNA-protein complex blocks the translation of the target mRNA.
  4. The mRNA is stored or degraded.
44
Q

What are the main characteristics of benign tumours?

A
  • not cancerous
  • grow slower than malignant tumours
  • covered in fibrous tissue that stops cells invading other tissues
  • harmless
  • can cause blockages
  • can put pressure on organs
  • can become malignant
45
Q

What are the main characteristics of malignant tumours?

A
  • cancerous
  • grow rapidly
  • invade and destroy surrounding tissues
  • spreads to other parts of the body in the bloodstream/ lymphatic system
46
Q

What is the role of tumour suppressor genes in the development of tumours?

A

Tumour suppressor genes can be inactivated due to a mutation in the DNA sequence.

Normally, tumour suppressor genes slow cell division - they produce proteins that stop cells dividing or cause apoptosis.

If the gene becomes inactivated, the protein isn’t produced so cells divide uncontrollably, resulting in a tumour.

47
Q

What are oncogenes?

A

Mutated proto-oncogenes.

48
Q

What do proto-oncogenes do?

A

They stimulate cell division by producing proteins that make cells divide.

49
Q

What is the role of oncogenes in the development of tumours?

A

The effect of a proto-oncogene can be increased if a mutation occurs (oncogene).

The gene can become overactive, stimulating cells to divide uncontrollably, resulting in a tumour.

50
Q

What is the role of abnormal methylation in the development of tumours?

A

Increased methylation of tumour-suppressor genes causes it to be unable to be transcribed. Their proteins aren’t produced so cell division isn’t slowed.

Decreased methylation of proto-oncogenes causes them to act as oncogenes. Production of their proteins is increased, encouraging cell division.

Cells divide uncontrollably, forming tumours.

51
Q

What is the role of increased concentration of oestrogen in the development of tumours?

A
  1. Oestrogen can stimulate breast cells to divide and replicate. More cell divisions increases chance of mutations so increases chance of cells becoming cancerous.
  2. Cancerous cells can be assisted by oestrogen, replicating faster, and forming tumours faster.
  3. Oestrogen can introduce mutations directly into the DNA of certain breast cells, increasing the chance of them becoming cancerous.
52
Q

How can cancer be prevented?

Related to oncogenes and tumour suppressor genes

A

The mutation of oncogenes or tumour suppressor genes can be screened for to make an early diagnosis.

53
Q

How can cancer be treated?

A

Drugs can be developed to target specific mutations.
Surgery can remove tumours and surrounding tissue.
Gene therapy can provide working versions of tumour suppressor genes.

54
Q

What have sequencing projects done?

A

Read the genomes of a wide range of organisms, including humans.

55
Q

What does determining the genome of simpler organisms allow?

How can this be applied in medicine?

A

The sequences of the proteins that derive from the genetic code (the proteome) can be determined

This can be used to identify potential antigens for use in vaccine production.

56
Q

What difficulties are there when sequencing the proteome of more complex organisms?

A

The presence of non-coding DNA and regulatory genes.

57
Q

How have sequencing methods evolved?

A

They are continously updated and have become automated.

Biology (21 decks)

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