Topic 4 - DNA, RNA And Proteins Synthesis Falshcards Flashcards

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1
Q

Meiosis

A

Cell division to form gametes

2 divisions, 4 daughter cells, genetically different (crossing over, independent segregation)

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2
Q

Mitosis

A

Cell division for growth and repair

1 division, 2 daughter cells, genetically identical

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3
Q

DNA, genes and chromosomes in EUKARYOTES

A

Long linear and double helix, folded in nucleus, folded into histones (proteins), folded into chromosomes, HAVE introns

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4
Q

DNA, genes and chromosomes PROKARYOTES

A

DNA is shorter and circular, no histones, no nucleus, HAVE plasmids, NO introns

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5
Q

DNA, genes and chromosomes mitochondria and chloroplasts

A

Have their own DNA, same as prokaryotes, NO plasmids

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6
Q

Protein synthesis - transcription and translation

A

Transcription (SCRIBE) - DNA to mRNA

Translation (TRANSLATING) -mRNA to amino acid/ protein/ polypeptide

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7
Q

Before meiosis

A

Early interphase - Diploid 2n (6 chromosomes, 3 homologous pairs)
Late interphase - Diploid 2x2n (6 chromosomes, 3 homologous pairs)

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8
Q

Meiosis stages

A
Prophase 1 (2x2n)- chromosomes condense, nuclear membrane breaks down
Metaphase 1 (2x2n)- homologous pairs line up, spindle forms, attaches to centromere
Anaphase 1 (2x2n)- homologous pairs separate, pulled to opposite poles
Telophase 1 (2xn)- nuclei reform, cell divides
Prophase 2 (2xn)- nuclei breaks down
Metaphase 2 (2xn)- chromosomes line up in equator, spindle forms, attaches to centromere
Anaphase 2 (2xn)- chromatids are separated, pulled apart to opposite poles 
Telophase 2 (n)- nuclei reforms, cell divides
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9
Q

Transcription

A

DNA helicase separates DNA strands breaking the hydrogen bonds and exposing bases
Free RNA nucleotides attach to the template strand through complementary base pairing
RNA polymerase joins nucleotides together to form pre-mRNA
Hydrogen bonds reform behind this
RNA polymerase reaches a ‘stop’ triplet code it detaches

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10
Q

Transcription in prokaryotes and eukaryotes

A

Prokaryotes - DNA to mRNA, no introns/ no splicing

Eukaryotes - DNA to pre mRNA to mRNA, introns/ splicing

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11
Q

Translation

A

Ribosomes binds on to the mRNA at a start codon
Codon is reattached to an anticodon by complementary base pairing
Ribosome hold tRNA in place
Amino acids are joined together with a peptide bond

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12
Q

tRNA

A

Polynucleotide, folded by hydrogen bonds, anticodon is specific to the amino acid it carries

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13
Q

Crossing over

A

Different combination of alleles

Occurs in metaphase 1, chromatids of homologous pairs cross over and swap alleles

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14
Q

Independent segregation

A

Different combination of chromosomes

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15
Q

Gene mutation and primary structure

A

DNA is degenerate, each amino acid is coded for by more than one triplet codon, changes to DNA base might not case a change to amino acid in primary structure, no change to bonding or tertiary structure

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16
Q

Mutations and non functional proteins

A

Changes to DNA triplet during replication, changes to mRNA codon, different anticodon and amino acid (changes primary structure), different bonding, changes tertiary structure

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17
Q

Introns

A

Regions within a gene that don’t code for polypeptides

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18
Q

Triplet code

A

3 bases = 1 amino acid

19
Q

What does a degenerate code do

A

Protects against point mutations (a single nucleotide base is changes)

20
Q

Transfer of information from DNA

A

Nucleotide base sequence determines the sequence of amino acids in proteins
Eukaryotes- DNA found in the nucleus by protein synthesis in the cytoplasm
DNA transferred into the cytoplasm by being transcribed onto a single stranded molecule (RNA)

21
Q

RNA

A

Single nucleotide chain
Polymer made of repeating mono nucleotide subunits
A,U,G,C
mRNA and tRNA

22
Q

mRNA description

A
Long strand, single helix
Formed in nucleus during transcription 
Small (leaves pores in nuclear envelope
Act as template for protein synthesis
Carries information in the form of codons, determines the amino acid sequence
23
Q

tRNA

A

Small, single stranded folded into a clover leaf shape

Anticodon - sequence of 3 organic bases coding for amino acids

24
Q

Splicing pre-mRNA to mRNA

A

Pre-mRNA is produced in transcription. The spliced to form mRNA
Introns prevent the synthesis of a polypeptide
mRNA passes through nuclear pores into cytoplasm where it is attracted to the ribosomes for translation

25
Q

Mutation

A

If a mutation occurs during gamete formation, then these may be inherited

26
Q

Gene mutation

A

a change to base sequences of DNA during DNA replication

27
Q

Calculating chromosome combinations

A

2^n when n = number of pairs of homologous chromosomes

2n)^2 when n = number of pairs of homologous chromosomes (when there are two different parents

28
Q

gamete

A

haploid sex cell

29
Q

Haploid

A

a cell with a single set of unpaired chromosomes

30
Q

diploid

A

a cell with two complete sets of chromosomes

31
Q

fertilisation

A

fusion of 2 haploid gametes to form a zygote

32
Q

chromosome non-disjunction

A

when chromosomes don’t separate properly during meiosis 1 or 2
> causes uneven number of chromosomes in the gamete

33
Q

homologous pairs

A

one chromosomes from each parent

same gene but different alleles

34
Q

parts of a chromosome

A

> centromere - joins two chromatids

> chromatids - exact copy of the other half

35
Q

substitution

A

swapping one base for a different base

36
Q

deletion

A

one base is removed (causing a frame shift)

37
Q

codon

A

triplet of bases on mRNA that codes for a specific amino acid

38
Q

anticodon

A

triplet of bases on tRNA that is complementary to codon on mRNA

39
Q

universal

A

genetic molecule in all living organism

40
Q

non-overlapping

A

each DNA triplet is separate from each other

41
Q

degenerate

A

the same amino acid can be coded for by more than one triplet

42
Q

genome

A

the complete set of genes in a cell/ organism

43
Q

proteome

A

the full range of proteins that a cell can make