Brainscape's Knowledge GenomeTM

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


See full index

IMMS > 1- Cells and Contents > Flashcards

1- Cells and Contents Flashcards

1
Q

What is the definition of the Karyotype?

A

Number and appearance of chromosomes in a cell. Arranged in size order, largest is pair 1 with the smallest pair 22.

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

What is the purpose of mitosis

A

Replace dead cells, growth and to produce two genetically identical daughter cells.
Repair

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

What stage of the cell cycle are cells that are not diving found in?

A

G0 phase

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

What occurs in the G1 growth phase of the cell cycle?

A

Rapid growth
Organelle production
Protein synthesis: including spindle formation
Normal metabolic function

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

What occurs in the synthesis stage of the cell cycle?

A

DNA replication
Centromere replication
Histone proteins double- 2x DNA at the end of the S phase.

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

What occurs during the G2 growth phase of the cell cycle?

A 
Chromosomes condense (coil up and become visible).
Energy stores accumulate
Mitochondria and centrioles double

Checks for mutations that are a risk in S phase

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

What are the stages of mitosis ?

A 
Interphase 
Prophase 
Prometaphase 
Metaphase 
Anaphase 
Telophase
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What occurs during interphase?

A

DNA and centrosome replication occurs, producing identical sister chromatids.
Lasts between 16 and 24 hrs

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

What occurs during prophase?

A

Chromatin condenses into chromosomes and mitosis spindle is formed.

Centrioles (centrioles) move to opposite poles of the nucleus.

Nuclear membrane begins to break down

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

What occurs during premetaphase

A

Nuclear membrane completely breaks down, releasing chromosomes into the cytoplasm (no nucleus present).

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

What occurs during metaphase?

A

Chromosomes line up along the equatorial plate (metaphase plate) of the cell.

Spindles attach to centromeres

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

What occurs during anaphase?

A

Centromerers split separating sister chromatids- they are pulled to opposite poles of the cell as the spindle fibres contract towards nuclear poles.

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

What occurs during telophase?

A

Cytokinesis

Chromosomes unfold into chromatin
Nuclear membrane forms
Organelles become evenly distributed around each nucleus
Cell divides producing two genetically identical daughter cells (2N)
46 chromosomes in each.

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

How would a nucleus appear on a histological slide if the cell was undergoing mitosis?

A

Dark- the chromatids have condensed into chromosomes

Nuclei would not be the same size

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

What is an indication that a tumour is malignant and not benign?

A

Increase in the number of mitotic divisions

Number of mitotic figures is used to determine severity of the cancer: more there is, the worse is it.

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

What are the key differences between mitosis and meiosis?

A

Only occurs in gametes
Two divisions
Produces 4 haploid daughter cells
Recombination of genetic material produces diversity
Produces 4 genetically different daughter cells
It is NOT cycle process: there is a start and finish

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

What are the stages of meiosis?

A

Meiosis 1
Meiosis II

Each can be seen to have a prophase, metaphase, anaphase and telophase

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

What occurs during meiosis I?

A

Prophase 1- crossing over occurs
Metaphase 1- random assortment occurs as chromosomes align at the equatorial plate
After this initial meiosis I division two daughter cells are produced with 2N number of chromosomes

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

What occurs during meiosis II?

A

Cells divide again producing 4 haploid daughter cells

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

What is gametogenesis?

A

Process in which preecursor cells undergo divisions and differentiate to form haploid gametes

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

In oogenesis when do oogonia enter prophase of meiosis I?

A

Eggs begin as premordia cells before undergoing 20-30 mitotic divisions too form oogonia

Following the formation of oogonia they enter prophase of meiosis I by the 8th month of intrauterine life

The meiosis process is then suspended

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

In oogenesis when is meiosis I completed and when does meiosis II commence?

A

Meiosis I is completed at ovulation forming a secondary oocyte (this receives most of the cytoplasm making it a big cell)

The other small cell is termed a polar body

Meiosis II is completed at fertilisation: this forms 3 polar bodies and one egg

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

During spermatogenesis when do meiotic divisions commence?

A

Primordial cells undergo around 30 mitotic divisions forming spermatogonia

Meiotic divisions do not commence until puberty

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

What are the stages of spermatogenesis?

A

Primary spermatocytes enter meiosis 1 emerging as haploid secondary spermatocytes

These undergo second meiotic divisions to form spermatids which develop into mature spermatozoa

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

Definition of non disjunction

A

Failure of chromosome pairs to separate in meiosis I or sister chromatids to separate in meiosis II

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

What is gonadal mosaicism? I

A

When precursor germ line cells to ova or spermatozoa are a mixture of two or more genetically different cell lines (one is mutated the other is not)- certain sperm cells will be mutated

Individual is not affected as mutation not in somatic cells- however all gametes from mutated germ line is affected.

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

When does risk of gonadal mosaicism increase?

A

With increasing paternal age- more time for mutations

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What does mitosis produce

A

2 diploid daughter cells that are genetically identical to parent cell.

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

What phases of the cell cycle make up interphase?

A

G1, S and G2

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

What is meiosis used for?

A

Production of gametes

31
Q

What does meiosis produce?

A

4 haploid daughter cells genetically different to the parent cell

32
Q

How is genetic diversity produced in meiosis I?

A

Prophase I- crossing over

Metaphase I- random assortment

33
Q

What is a multifactorial disease?

A

Disease due to genetic and environmental factors (e.g schizophrenia and diabetes).

An individual may have a genetic predisposition but am adverse environmental trigger is required for onset.

34
Q

Definition of genotype

A

Genetic constitution of an individual

35
Q

Definition of phenotype

A

Appearance of an individual (physical, biochemical and physiological) which results from interaction of genotype with the environment.

36
Q

Definition of allele

A

One of several alternative forms of a gene at a specific loci.

37
Q

What is the longest phase of the cell cycle?

A

Interphase

38
Q

What is the most common inheritance pattern for gonadal mosaicism?

A

X-linked or autosomal dominant

It’s more common in males

39
Q

What conditions is gonadal mosaicism observed in?

A

Osteogenesis imperfecta and duchenne muscular dystrophy

40
Q

Definition of locus

A

Position of gene/ DNA on the genetic map

41
Q

What is a wild type allele?

A

Non mutagenic alleles are termed wild types whilst pathogenic mutations / variants are carried on disease alleles

42
Q

What is consanguinity ?

A

Reproductive union between 2 relatives: descended from the same ancestor.

43
Q

Definitions of homozygous, heterozygous and hemizygous.

A

Homozygous: both alleles of a gene at a particular loci are the same.

Heterozygous: both alleles of the same gene at a particular loci are different

Hemizygous: only one allele of a gene is present at a particular locus.

44
Q

What are polymorphisms?

A

Frequent hereditary variations at a particular locus- they do not cause problems, the mutations do.

They can make you more / less efficient or more / less susceptible to a disease.

45
Q

Define autozygosity

A

Homozygous by descent

Inheritance of the same mutant allele through two branches of the same family

46
Q

Define penetrance

A

Proportion of people with a particular gene / genotype that show the expected phenotype.

47
Q

Difference between complete and incomplete

A

Complete: gene / genes for a trait are expressed in all the population.

Incomplete: genetic trait is only expressed in parts of the population.

48
Q

Definition of variable expression

A

Variation in clinical features (type and severity) between individuals with the same gene alteration.

49
Q

Define sex limitation

A

Expression of a particular characteristic is limited to one of the sexes.

50
Q

Term for a condition that manifested at birth

A

Congenital

51
Q

What is KNudson’s two hot hypothesis?

A

Gene mutations can be inherited OR acquired during a person’s life

  • sporadic cancers: 2 acquired mutations
  • hereditary cancers: 1 inherited and 1 acquired mutation
52
Q

4 examples of genetically inherited diseases

A

Down’s syndrome- non dysfunction chromosome 21
Cystic fibrosis
Huntington disease
Haemophilia

Individually rare but cumulatively enough to have genetic services

53
Q

4 examples of multifactorial diseases

A

Spina bifida
Cleft lip
Diabetes
Schizophrenia

Main cause of disease in developed countries

54
Q

4 environmental causes of disease?

A

Poor diet
Infection
Drugs
Accidents

Main cause of disease in third world countries and A&E

55
Q

What are the two Mendelian forms of inheritance?

A

Autosomal vs sex linked

Dominant vs recessive

56
Q

Give the typical features of autosomal recessive inheritance

A
  • Occurs in homozygous state (two copies of recessive allele must be present)
  • Affects males and females equally
  • If two parents are carries = 25% chance offspring will have disease and 50% chance they will be carriers.
  • Calculations at conception: healthy siblings have 2/3 chance of being carriers
  • Affected individuals in a single generation
  • Parents can be related e.g consanguineous (recessive conditions most common in these types of families.

When calculating risk probabilities of offspring, the affected child in disregarded.

57
Q

Give an example of an autosomal recessive condition

A

Cystic fibrosis:

  • most common autosomal recessive condition affecting white males in the UK
  • incidence of 1 in 25,000
  • Population carrier frequency is 1 in 25
58
Q

Definition of expressivity

A

Range of phenotypes expressed by a specific genotype

59
Q

Definition of anticipation

A

Where a genetic disorder affects successive generations earlier or more severely.

60
Q

Give the key features of autosomal dominant inheritance

A
  • Disease that manifests in heterozygous state
  • Affects males and females in equal proportions
  • Affected individuals in multiple generations
  • ONLY WAY TO PASS DISEASE FROM MALE TO MALE
  • 50% chance of offspring having the condition
  • Can appears to skip a generation but this is due to penetrance and variable expression
  • Example: Huntington’s disease
61
Q

Give the key features of X-linked inheritance

A
  • Caused by a mutation on the X chromosome
  • Usually affects females more than males
  • Affected males cannot pass mutation to son, all daughters of affected males are carries.
  • Males cannot be carriers
  • Usually inherited from unaffected mothers
  • X-linked dominant condition: Alports syndrome
  • X-linked recessive condition: Duchenne muscular dystrophy
62
Q

Define lyonisation

A

Process of X chromosome Inactivation

One of the 2 X chromosomes in randomly inactivated in early embryonic development

The X chromosome is inactivated to prevent women having twice as many gene products from the X chromosome as males

Only functional copy of the X chromosome

63
Q

What is an ideogram

A

A diagrammatic form of chromosome bands

The bands are numbered according to their distance from the centromere

64
Q

What is Mendel’s second law?

A
  • Law of independent assortment

- Alleles of one gene sort into gametes independently of alleles of another gene.

65
Q

Would an X-linked dominant condition be more common in males or females?

A

They occur twice as frequently in females as they do males.

66
Q

Is an x-linked recessive condition more common in males or females?

A

Males

67
Q

Define sex limitation

A

Both sexes have a particular gene but it’s expression is limited to only one of the sexes

68
Q

Which parent is all our mitochondrial DNA inherited?

A

Mother

69
Q

Stages in the production of a thin cell microscope slide

A
  • Tissue fixed in formalin
  • Samples embedded in paraffin
  • Fine slices mounted on microscope slide
70
Q

What does H&E stain

A

Haematoxyoin- stains nuclie and other acidic substances blue
Eosin- stains cytoplasm and extra cellular fibres pink

71
Q

Used of periodic acid schiff

A

Stains sugars magenta !

72
Q

Use of van giesan stain?

A

Stains elastic tissue brown !

73
Q

Use of trichrome stain?

A

To stain 3 different types of cell 3 different colours all within the same section

Most common = Masson’s trichrome

74
Q

Use of Alcian blue stain?

A

Stains mucins blue

IMMS (1 decks)

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