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Flashcards in voice of the genome Deck (31)
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1
Q

describe the structure of the nucleus

A

large organelle surrounded by a nuclear envelope which contains many pores, the nucleus contains chromatin, and a nucleolus

2
Q

what does the smooth endoplasmic reticulum do?

A

synthesises and processes lipids

3
Q

describe the structure of a mitochondrion

A

oval shaped, with a double membrane and inner folded structures called cristae, inside is the matrix

4
Q

describe the structure of a centriole

A

small, hollow cylinders made of microtubules

5
Q

what happens to proteins as they go through the rER?

A

they are folded, assuming 3D shape, and sugar chains are added

6
Q

what happens to proteins in the golgi apparatus?

A

they undergo further processing, further side chains etc. are added

7
Q

name 3 differences between light microscopes and electron microscopes

A
  • light microscopes use light to form an image whereas electron microscopes dont
  • light microscopes have max resolution of 0.2 micometers, e- microscopes have max res. of 0.0002 um
  • max useful magnification of a light mic. is x1500, whereas its x1,500, 000 for e-
8
Q

how do you calculate magnification?

A

size of image/size of real object

9
Q

what is meant by the term ‘tissue’?

A

a group of similar cells that are specially adapted to work together to carry out a particular task

10
Q

what is meant by the term ‘organ’?

A

an organ is a group of different tissues that work together to perform a particular function

11
Q

what is meant by the term ‘locus’?

A

the position on the chromosome in which the alleles for a gene are found

12
Q

what is the effect on gene expression when acetyl groups are removed from the histone proteins?

A

the chromatin becomes highly condensed, and genes cannot be transcribed

13
Q

what is meant by the term ‘polygenic’?

A

when characteristics are controlled by a number of genes at different loci

14
Q

what is meant by the term ‘sex linked’?

A

when the locus of the allele that codes for it is on a sex chromosome

15
Q

describe the events of metaphase

A

chromosomes line up along the middle of the cell and become attached to the spindle by their centromere

16
Q

describe the events of anaphase

A

centromeres divide, separating each pair of sister chromatids, spindles contract, pulling chromatids to opposite ends of the spindle

17
Q

order the four stages of mitosis

A

prophase, metaphase, anaphase, telophase

18
Q

what do transcription factors do?

A

alter the rate of transcription

19
Q

what is an operon?

A

a section of prokaryotic DNA that contains a cluster of genes that are transcribed together with control elements and a regulatory gene

20
Q

what does a promotor do?

A

its an area before the structural gene that allows RNA polymerase to bind to

21
Q

what does the regulatory gene do?

A

codes for an activator or repressor

22
Q

what is meant by ‘epigenetic changes’?

A

the attachment or removal of chemical groups from the DNA in order to alter how easy enzymes associated with transcription can interact with the gene

23
Q

what is continuous variation?

A

when the individuals within a population vary within a range, with no distinct categories

24
Q

what is discontinuous variation?

A

when there are two or more distinct categories, and each individual fits into only one category

25
Q

what is cancer?

A

uncontrolled division of cells that leads to tumour formation, it is influenced by genes and environment

26
Q

How does increased methylation alter gene expression?

A
  • methyl group attaches to CpG site

- increased methylation alters the structure so that the proteins and enzymes needed for transcription cant bind

27
Q

what are histones?

A

the proteins that DNA is wrapped around to form chromatin

28
Q

How does more acetylation affect gene expression?

A
  • chromatin less condensed

- proteins can bind to gene

29
Q

How can epigenetic changes be passed on?

A

cell divides and replicates, usually the epigenetic changes are removed, some escape the removal process

30
Q

name two uses for stem cells

A
  • used to repair damaged nerve tissue in spinal cord injuries
  • replace damaged cardiac tissue after a heart attack
31
Q

describe the events of prophase

A

chromosomes condense, centrioles move to the opposite ends of the cell and the spindle fibres form, nuclear membrane breaks down