voice of the genome

Question 1

describe the structure of the nucleus

Answer 1

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

Question 2

what does the smooth endoplasmic reticulum do?

Answer 2

synthesises and processes lipids

Question 3

describe the structure of a mitochondrion

Answer 3

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

Question 4

describe the structure of a centriole

Answer 4

small, hollow cylinders made of microtubules

Question 5

what happens to proteins as they go through the rER?

Answer 5

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

Question 6

what happens to proteins in the golgi apparatus?

Answer 6

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

Question 7

name 3 differences between light microscopes and electron microscopes

Answer 7

• 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-

Question 8

how do you calculate magnification?

Answer 8

size of image/size of real object

Question 9

what is meant by the term ‘tissue’?

Answer 9

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

Question 10

what is meant by the term ‘organ’?

Answer 10

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

Question 11

what is meant by the term ‘locus’?

Answer 11

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

Question 12

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

Answer 12

the chromatin becomes highly condensed, and genes cannot be transcribed

Question 13

what is meant by the term ‘polygenic’?

Answer 13

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

Question 14

what is meant by the term ‘sex linked’?

Answer 14

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

Question 15

describe the events of metaphase

Answer 15

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

Question 16

describe the events of anaphase

Answer 16

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

Question 17

order the four stages of mitosis

Answer 17

prophase, metaphase, anaphase, telophase

Question 18

what do transcription factors do?

Answer 18

alter the rate of transcription

Question 19

what is an operon?

Answer 19

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

Question 20

what does a promotor do?

Answer 20

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

Question 21

what does the regulatory gene do?

Answer 21

codes for an activator or repressor

Question 22

what is meant by ‘epigenetic changes’?

Answer 22

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

Question 23

what is continuous variation?

Answer 23

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

Question 24

what is discontinuous variation?

Answer 24

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

Question 25

what is cancer?

Answer 25

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

Question 26

How does increased methylation alter gene expression?

Answer 26

• methyl group attaches to CpG site

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

Question 27

what are histones?

Answer 27

the proteins that DNA is wrapped around to form chromatin

Question 28

How does more acetylation affect gene expression?

Answer 28

• chromatin less condensed

- proteins can bind to gene

Question 29

How can epigenetic changes be passed on?

Answer 29

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

Question 30

name two uses for stem cells

Answer 30

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

Question 31

describe the events of prophase

Answer 31

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