genetics and epigenetics Flashcards

1
Q

How many chromosomes does each cell contain?
(Marshall, 2017).

A

22 pairs of chromsosomes
1 pair of sex chromosomes.

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1
Q

What is the genotype?
(Marshall, 2017).

A

The complete genetic make up of an organism.

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2
Q

What is the phenotype?
(Marshall, 2017).

A

The observable expression of the genotype, how these genes present as physical appearance.
e.g. hair and eye colour

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3
Q

What do genes code for?
(Marshall, 2017).

A

proteins, the building blocks of cells responsible for many functions.

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4
Q

What are some functions of proteins?
(Marshall, 2017).

A
  • Enzymes e.g. lipases
  • Structural Support e.g. collagen
  • Transport: e.g. haemoglobin.
  • Hormones e.g. insulin
  • Immune Response:
  • Cell Signaling
  • Storage and Transport of Molecules
  • Defense and Protection
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5
Q

How are proteins made?
(Marshall, 2017).

A

3 nucleotides (or bases) form a code -AT,CG
These groups of three form an amino acid
Amino acids form chains by linking together and bond to form the shape of the protein
The shape of the protein determines its specific function.

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6
Q

How are chromosomes made?
(Marshall, 2017).

A

DNA, wraps around proteins called histones to form chromatin.

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7
Q

Describe dominant and recessive genes.
(Marshall, 2017).

A

In a chromosome pair, each chromosome is contributed to the child from the parent.
From one gene, the child may inherit a dominant gene (A) or a recessive gene (a), meaning there are many possibilties for the pair of genes inherited.
They can be both dominant (AA), both recessive (aa), or one of each.

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8
Q

What are the three laws of inhertience?
(Marshall, 2017).

A

Law of Segregation: When organisms reproduce, the traits they pass on (like eye color or height) separate out randomly. So, offspring get one version of each trait from each parent.
Law of Independent Assortment: Different traits are passed on independently of each other. Just because you inherit blue eyes from your mum doesn’t mean you’ll necessarily inherit her height or hair color.
Law of Dominance: Some traits are stronger than others. If you inherit a dominant trait (like brown eyes) and a recessive trait (like blue eyes), the dominant one will usually show up in how you look. You’d need two copies of the recessive trait to see it.

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9
Q

What are the different types of imperfect processes?
(Marshall, 2017).

A

Chromosomal disorders
- large scale, chromosome additions or deletions.
- no mutation in individual genes
Single point abnormalities
- Alteration in one nucleotide, missense, non-sense, insertion, deletion
Multifactoral inheritance aka complex cell disorders
- these involve mutliple genes

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10
Q

What are the different types of chromosome disorders?
(Marshall, 2017).

A

Monosomy- missing chromosome
Trisomy- additonal chromosome
Chromosomes can be in full, moscial or partial forms. Mosaic has the presence of cells with different chromosomal compositions.
Partial have structural abnormalities or are missing a portion of their genetic material.

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11
Q

Describe missense, non-sense, insertion, deletion, framshift and duplication.
(Campbell, 2020)

A

A missense mutation occurs when there is a mistake in the DNA code and one of the DNA base pairs is changed, for example, A is swapped for C.
Nonsense mutation also involves a single alteration to the DNA base pair but in the case of a nonsense mutation, the change results in the production of a stop codon terminating protein synthesis prematurely.
An insertion mutation involves the addition of one (or more) nucleotide base pairs into the DNA sequence.
Deletion mutation occurs when there a piece of DNA is removed from the sequence. The size of the DNA that is removed can vary in length, from a single base pair to an entire gene or several consecutive genes.
Frameshift occurs when the aforementioned “addition” or “deletion” mutations result in a change to the gene’s reading frame, which includes groups of three bases that encode for an amino acid. The change in the reading frame alters the grouping of the bases and subsequently changes the amino acids that are encoded.
Duplication is when a piece of DNA is (abnormally) copied. This might happen once or several times, and can therefore impact the functionality of the encoded protein.

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12
Q

What are X-linked disorders?
(Marshall, 2017).

A

As females have two copies (XX), if the disorder is recessive and only present on one of the copies of the X, they become a carrier.
Males only have one copy of the X chromosome, this means a recessive gene is on the X chromosome they are affected.
The presence of a dominant mutated gene will always result in an affected individual.

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13
Q

Give some examples of genetic disorders.
(Marshall, 2017).

A

Missense- sickle cell disease
Nonsense- Cystic fibrosis
Insertion- Huntington disease, Down’s syndrome (Trisomy 21)
X-Linked Recessive- muscluar dystrophy

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14
Q

How are cells replicated?
(Marshall, 2017).

A

Interphase:
- before it divides the cell has a period of growth and prepration called interphase
- this phase has 3 stages: G1, S, and G2
- in the S stage (synthesis) DNa replication occurs, reuslting in the cells genetic material being duplicated
Mitosis
- when the duplicated chromosomes are distributed into two daughter cells
- has several stages: prophase, metaphase, anaphase, and telophase.
- prophase: chromatin condenses into visible chromosomes, and the nuclear envelope breaks down. Spindle fibers, composed of microtubules, begin to form and attach to the centromeres of the chromosomes.
-metaphase: chromosomes align along the metaphase plate, in the middle of thee two poles of the cell.
- anaphase: sister chromatids of each chromosome separate and move toward opposite poles of the cell, pulled by the spindle fibers.
- telophase: the separated chromatids reach the poles, and new nuclear envelopes form around them. The chromosomes begin to decondense back into chromatin.
Cytokinesis: the division of the cytoplasm, resulting in the formation of two distinct daughter cells.
The result of cell replication is two genetically identical daughter cells, each containing a complete set of chromosomes and organelles. This process ensures the growth and renewal of tissues and the transmission of genetic material to offspring in organisms.

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15
Q

How is genetic code used to make proteins (gene expression)?
(Marshall, 2017)

A

There are two main stages- transcription and translation.

16
Q

Why is it important to consider genetics in nursing?
(Camak, 2016)

A

Genetics is integreated into many aspects of care and its improtant for nurses to have a good understanding and be prepared to apply this information in practice:
* pharmacogenetics
* identyfying and screening for genetic disorders
* monitior the effectiveness of treatment interventions
* adress patient and family advocacy needs.

17
Q

What is the Angelina Jolie effect?
(Liede, 2018)

A

Angelina Jolie publicly announced she had undergone a risk-reducing mastectomy after learning through genetic testing she is a BRCA1 mutation carrier.
This created a rise in public awareness in genetic testing and resulted in a raise in internet searches, genetic testing, and masectomy rates.

18
Q

What are the ethical considerations with genetic testing?
(Charron, 2022)

A
  • informed consent: ensuring patients understand the risks, benefits, and impacts of the test results, ensuring they dont feel pressured.
  • psychological impacts: learning about disease or condition they have may have a huge psychological impact on an individual or their loved one
  • privacy and confidentiality: its a very senstice topic andf can result in discriminataion e.g. from employers
  • impact on family dynamics: can affect relationships and the ethical questionof whether to share results with family members or not
  • reproductive decision making: can influence reproductive decision making including whther to terminate a pregnancy
19
Q

Describe transcription.
(Marshall, 2017)

A

Transcription- DNA makes RNA
* RNA polymerase binds to the promoter region of the DNA molecule, marking the beginning of transcription.
* RNA polymerase unwinds the DNA double helix and adds complementary RNA nucleotides (ACGU) to the growing mRNA chain.
* The enzyme reads the DNA template strand in the 3’ to 5’ direction and synthesizes the mRNA strand in the 5’ to 3’ direction.
* Transcription continues until RNA polymerase reaches a termination sequence in the DNA template, signaling the end of transcription.
* The mRNA molecule is then released from the DNA template.

20
Q

Describe translation.
(Marshall, 2017).

A

Translation: RNA makes proteins, the genetic information encoded in mRNA is used to assemble a specific sequence of amino acids into a protein.
* The mRNA molecule binds to a ribosome, and the ribosome scans the mRNA until it finds the start codon, marking the beginning of translation. tRNA binds to the srat codon.
* The ribosome moves along the mRNA molecule in the 5’ to 3’ direction, and at each codon, a corresponding tRNA molecule carrying the appropriate amino acid binds to the mRNA through complementary base pairing.
* Peptide bonds form between adjacent amino acids, catalyzed by the ribosome, creating a growing polypeptide chain. The ribosome then translocates to the next codon, and the process repeats.
* Translation continues until a stop codon is encountered on the mRNA
* release factors bind to the ribosome, causing the completed polypeptide chain to be released. The ribosome dissociates from the mRNA, and the newly synthesized protein is free to fold into its functional three-dimensional structure.