Brainscape's Knowledge GenomeTM

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


See full index

Yr 12 Bio > Ch3 > Flashcards

Ch3 Flashcards

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

true or false; a cell expresses all the genes of its genome at the same time and same rate

A

false

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

why are some genes active while others are inactive?

A

to ensure ensures energy is not wasted and unwanted proteins aren’t produced

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

gene regulation

A

the process that enables the gene to be expressed within a cell

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

what’s the central Dogma of biology

A

protein synthesis (transcription and translation)

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

what factors effect gene expression

A

non-coding DNA
Chemical influences
Gene production
Environmental influence
Bacteria

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

how does bacteria affect gene expression

A

E. coli can synthesize its own tryptophan and tryptophan is an amino acid that affects gene expression

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

how does the environment affect gene expression

A

in some situations the environment has an influence on the DNA methylation
stress and diet can cause epigenetic changes eg) Himalayan rabbit has a white body with black extremities

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

how do chemical influences affect gene expression

A

chromatin can be moved around and expose different genes to chemical influences
methyl compounds can cause methylation where genes become inactive ‘turned off’
x-inactivation is an example of this
eg) tortoise shell cats

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

how are genes ‘turned off’

A

cytosine bases in DNA are often modified and are said to be methylated, methylation switches off gene expression b/c it blocks RNA polyermase from bonding to DNA
the gene is silenced

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

how are genes ‘turned on’

A

acetyl groups can be added to histones to become active
they cause the nucleosome to unwind and expose genes to RNA polymerase
environmental factors can also cause change in chemical signatures

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

what is epigenetics

A

the study of inheritable changes in gene expression without changes in DNA sequences. epigenetics controls gene expression by turning on or off genes

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

what’s the term to describe the mechanisms of DNA methylation, histone modification, imprinting, non-coding RNA and post-translational modifications

A

Epigenetics

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

what’s imprinting

A

the process by which only one copy of a gene in an individual (either from their mother or their father) is expressed, while the other copy is suppressed.

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

what are post-translational modifications

A

the process of covalently adding a chemical group to an amino acid in a protein after the protein has been synthesized.

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

what is histone modification

A

the process in which histones may undergo divergent epigenetic changes which may trigger transcriptional activation or repression

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

true or false; proteins, including enzymes and structural proteins, are essential to cell structure and functioning

A

true

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

what are enzymes

A

biological catalysts (proteins) that speed up rates of reaction

18
Q

true or false; phenotype is determined by protein expression

A

true

19
Q

Whats DNA’s main roll

A

to produce proteins to carry out cel function

20
Q

what’s a codon

A

the triplet base sequence that determines what amino acid is produced eg) CAG – glutamine, GAG – glutamic acid

21
Q

where does transcription occur

A

nucleus

22
Q

where does translation occur

A

ribosomes

23
Q

what happens in the first step of protein synthesis

A

the template strand of DNA is unzipped by DNA helicase then a single stranded RNA copy is produced called pre-messenger RNA (pre-mRNA) by RNA polymerase

24
Q

what’s RNA polymerase

A

A

25
Q

Where does RNA polymerase start creating a complementary mRNA strand during transcription

A

RNA polymerase bonds to the promoter region, creates the complementary mRNA strand, a stop signal is reached & pre-mRNA is released

26
Q

what occurs during splicing

A

introns are spliced from pre-mRNA to from mRNA, leaving only exons

27
Q

what are the 4 differences between DNA and RNA production

A

RNA
- a segment of DNA is copied
- RNA polymerase joins nucleotides
- Produces single stranded RNA
- found in nucleus and cytoplasm

DNA
- the entire DNA is copied
- DNA polymerase joins nucleotides
- Produces double stranded DNA
- found in cytoplasm

28
Q

what occurs during translation

A

ribosomes synthesis polypeptides/proteins from tRNA using mRNA codons

29
Q

what does translation synthesise

A

proteins

30
Q

what does tRNA stand for and what does it do?

A

Transfer RNA
transfers specific amino acids from cytoplasm to ribosomes

31
Q

when does a ribosome stop synthesising a protein?

A

when a stop codon is reached

32
Q

does translation require ATP

A

yes

33
Q

what are histones?

A

DNA wraps itself around histones in the nucleus, 8 histones form a nucleosome and nucleosomes make up chromatin which makes up chromosomes

34
Q

what does the term methylated mean in terms of gene expression

A

when cytosine bases in DNA are modified or methylated they switch of gene expression by blocking RNA polymerase from bonding to DNA
the gene is silenced

35
Q

what are the two types of regulatory proteins

A

Activators – bind to DNA activating gene expression
enable DNA to unwind from histones
assist RNA polymerase to promoter regions

Repressors - bind to DNA switch off gene expression
can bind to promoter region to block RNA polymerase

36
Q

Whats found at each end of pre-mRNA

A

methylated cap added at the 5’ end and a poly-A tail containing 100-200 adenines at the 3’ end

37
Q

what happens to protein synthesis when DNA is packaged into chromatin

A

by default, genes are ‘switched off’ (proteins won’t be made)

38
Q

what are transcription factors

A

regulatory proteins that bind to DNA (can be activators or repressors)

39
Q

how can translation be prevented in a cell?

A

Can occur by:
binding-proteins attach to specific sequence on mRNA to block the ribosome from assembling onto mRNA strand and preventing translation

microRNAs (miRNAs) – are complementary to mRNA sequence & when bonded, will form a dsRNA to prevent translation (only in plants & animals)

40
Q

what’s lac operon

A

a segment of E. Coli’s DNA that consists of an operator, a promotor and 3 genes side by side that code for 3 enzymes involved with digesting lactose/glucose

if lactose is absent, or low, the repressor protein binds to the operator, covering part of the promoter. RNA polymerase can’t bind to the promoter & transcription of the 3 genes is blocked
if lactose is present, it binds to the repressor, altering its shape so that it can’t bind to the operator. The 3 genes are able to be transcribed to form the enzymes.

Yr 12 Bio (14 decks)

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