P1B3 - Genetics Flashcards

You may prefer our related Brainscape-certified flashcards:
1
Q

What is meiosis?

A

Cell division of four genetically non-identical daughter cells.
Meiosis is used in sexual reproduction.

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

Process of meiosis?

A

During meiosis, each pair of chromosomes replicate and the cell splits in two.

There are now two identical cells.
The diploid cell divides again.
Cells split

This creates four genetically different gametes that each have half the number of chromosomes of the parent cell.

Once the gametes fuse, the new cell divides by mitosis.
As soon as the embryo reaches a certain size, cells begin to differentiate (specialise).

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

Features of asexual reproduction?

A

No gamete fusion
1 parent
Offspring are clones
Cells divide by mitosis

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

Advantages of asexual reproduction?

A

No mate required
Identical offspring
Faster

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

Advantages of sexual reproduction?

A

Variation in offspring
Humans can speed up artificial selection through selective breeding of plants and animals.

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

What is DNA?

A

Dna is made up of polymers coiled up to form a double helix

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

What is a gene?

A

A small section of DNA.

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

What do genes do?

A

Genes code for a sequence of amino acids, which combine to give a specific protein.

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

What are chromosomes?

A

Long strands of DNA are coiled up to form chromosomes.
Chromosomes contain many genes.

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

How many chromosomes does a human body cell contain?

A

46
23 pairs

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

What is a genome?

A

The genome is the entire (all) genetic material of an organism.

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

DNA extraction practical steps?

A

Grind a sample of strawberry in soapy water
This breaks open cells, releasing the DNA from within cells.
Filter the sample
Very slowly, pour ice-cold ethanol into the filtrate.
The DNA moves into the ethanol by precipitation, and can then be removed with a wire loop.

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

In what year was the Human Genome Project?

A

2003

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

What did we understand about the HGP project for future benefits?

A

Gene identification
Personalised medicine
Gene therapy
Improved understanding of inherited diseases
Early diagnosis

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

What’s an allele?

A

Different variations of the same gene.
eg. blue eyes, brown eyes.

(Gene IS the eye colour.)

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

What is the genotype? What is the phenotype?

A

Genotype - The allele combination code - eg. BB Bb

Phenotype - The characteristic expressed due to the genotype - eg. XX is for FEMALE. Female is the phenotype.

17
Q

What does hereditary mean?

A

If a characteristic or disease/illness can be inherited.

18
Q

What is a mutation?

A

A change in a gene that creates a new allele

19
Q

How can a mutation cause variation?

A

Mutations mostly take place during cell division when a mistake is made copying a DNA.

A change in the DNA base sequence COULD change the amino acid sequence which COULD change the protein synthesis in the ribosomes.

20
Q

What is a protein?

A

Polymers made from a long chain of amino acid monomers

21
Q

What is mRNA?

A

Messenger RNA

22
Q

Why can’t DNA leave the nucelus? What happens instead?

A

DNA is too large of a molecule.
Instead the base sequence is sent to the ribosomes using mRNA.

23
Q

What are the 2 stages of protein synthesis?

A

Transcription (nucleus) - Forms short mRNA strand (U)

mRNA exits nucleus and travels to ribosomes

Translation (ribosomes) - Forms a polypeptide chain

24
Q

What happens during transcription?

A

An enzyme (RNA) Attaches to DNA strand right before the targeted gene base sequence

The enzyme unzips the DNA strand and moves along the DNA template

Enzyme then adds complimentary RNA nucleotides and are attached together to form a strand of mRNA. (T’s are replaced with U’S in mRNA)

25
Q

What happens during translation in protein synthesis?

A

mRNA strand travels out of nucleus via nuclear pores and travels into the cytoplasm

A ribosome moves along the mRNA strand and reads 3 bases at a time (triplet codons)

This is repeated for the whole strand, then the ribosomes attach the amino acids together

The tRNA molecules and the ribosomes detach from the amino acid chain, from which it can then fold up on itself thus forming a polypeptide protein.

26
Q

What determines a persons blood group?

A

A, B, AB, O

27
Q

What are the possible genotypes for the phenotypes A,B,AB,O

A

A - iA iA , iA iO
B - iB iB , iB iO
AB - iA , iB
O - iO iO

iA and iB are codominant while iO is recessive.

28
Q

What is a nucleotide?

A

The basic building block of nucleic acids (RNA and DNA)

29
Q

What is a nucleotide made up of?

A

Phosphate (circle)
Sugar (pentagon)
Base (rectangle)

30
Q

What do the bases pair with?

A

A - T
G - C

31
Q

What holds DNA bases together?

A

Weak hydrogen bonds

32
Q

What is cystic fibrosis?

A

Cystic fibrosis is a inherited disorder of cell membranes.
It causes thick, sticky mucus to build-up in the lungs and digestive system.

33
Q

what is it called when dna bases r grouped into 3?

A

Triple codon
determining the amino acid (1 out of 20)

34
Q

What bases change in the mRNA?

A

U base instead of T.

ACGAU
UGCUA