cytology

Question 1

what is a cytosol

Answer 1

largely water but also sugars proteins and salts.

viscous liquid

Question 2

what are inclusions

Answer 2

various substances found in some cells but not others

e.g melanin in retinal pigment epithelium.

Question 3

what are microfilaments

Answer 3

help in migration process and phagocytosis

Question 4

what are microtubuls

Answer 4

form cillia
hair like appendages on the surface of many cells
move gluid

Question 5

what does a nucleoplasm contain

Answer 5

chromatin and nucleolus within a matrix

Question 6

what is the structure of a nucleotide

Answer 6

deoxyribose
phosphate
base (4)

Question 7

what is a gene

Answer 7

dna that codes for the production of a particular protein

Question 8

what are coding portions of dna called

Answer 8

exons

Question 9

what is the size of muscle cells

Answer 9

2 micrometres

Question 10

what is the size of muscle cells

Answer 10

30 cm

Question 11

what is the size of nerve cells

Answer 11

1 m

Question 12

what does a general cell consist of

Answer 12

plasma memrane
cytoplasm
organelles
nucleus

Question 13

what are the functions of cell membrane

Answer 13

integrity of cell:

• not generally permeable
• surfaces of epithelial cells have different permeabilities.

specific regulation of passage:
-specific and selective gates

communication site:
-receptors for molecules such as hormones

Question 14

what are integral proteins

Answer 14

span the plasma membrane
act as gates
act as receptors

Question 15

what are peripheral proteins

Answer 15

co enzymes

help function of proteins

Question 16

what is the function of membrane proteins?

Answer 16

• transport
• enzymatic activity
• receptors for signal
• transduction
• intercellular joining
• cell-cell recognition
• attachment to the cytoskeleton and extracellular matrix

Question 17

What is Glycocalyx?

Answer 17

sugar coating of the cell attached mainly to integral proteins

• enables sperm to recognize egg cell
• signals which cells should be destroyed by phagocytosis
• determines ABO blood group of red blood cells

Question 18

what are the three different types of junctions between cells

Answer 18

• sticky glycoproteins on cell surface (glue)
• mechanical junctions
• specialised cell-cell junctions.

Question 19

what are mechanical junctions

Answer 19

-ball and socket joint
-tongue and groove
between lens fibres

Question 20

what are occluding junctions

Answer 20

• adjacent protein molecules in opposing plasma membranes fuse
• prevents the passage of molecules between cells.

Question 21

what are anchoring junctions

Answer 21

adhering junctions or desmosomes
found in skin epithelium,
cardiac muscle and uterus.
very robust.

Question 22

what are desmosomes

Answer 22

• plaques are anchored to the inside of the cell by intermediate filaments
• plaques of adjacent cells are linked by cadherins.

Question 23

what is a belt desmosome

Answer 23

long way round the cell

Question 24

what is hemidesmosome

Answer 24

plasma membrane to cytoplasm

Question 25

what is a spot desmasome

Answer 25

small area. | macula adherens

Question 26

what are gap junctions

Answer 26

adjacent cells joined by membrane proteins. | proteins allow cytoplasmic continuity so molecules can pass between cells

Question 27

what are the junctions between membrane proteins in gap junctions known as?

Answer 27

connexons

Question 28

where does the lens receive nutrients from?

Answer 28

aqueous humour

Question 29

why are cells that make up the lens joined by gap junctions?

Answer 29

so nutrients can diffuse from the lens surface to cells in its interior.

Question 30

what is a cytoskeleton and its function?

Answer 30

cell skeleton gives shape mediates cytoplasmic movements of organelles

Question 31

what are intermediate filaments?

Answer 31

hold everything tgether | respond and change length

Question 32

what does the centrosome in microtubules contain?

Answer 32

centrioles at right angles to each other | important for cell replication

Question 33

what is the nucleus?

Answer 33

control centre regular shape in normal cells nuclear pores-selective movement of cells

Question 34

where are ribosomes made?

Answer 34

nucleolus

Question 35

what is the function of chromatin?

Answer 35

makes up our chromosomes | intertwined DNA and histone proteins

Question 36

where is our genetic information stored?

Answer 36

chromosomes.

Question 37

what are complimentary base pairs linked by?

Answer 37

hydrogen bonds

Question 38

what is 1 amino acid coded for by?

Answer 38

codon | 3 adjacent nucleotides.

Question 39

what is transcription?

Answer 39

triplet codes of a gene are copied into a molecule of mRNA

Question 40

what is translation?

Answer 40

mRNA combines with complimentary tRNA molecules join to form the protein.

Question 41

what are synthesised proteins packaged by?

Answer 41

golgi apparatus

Question 42

how many pairs of autosomes and sex chromosomes do we have?

Answer 42

22 pairs of autosomes | one pair of sex chromosome