Cell structure (basic)

Question 1

Nucleus

Answer 1

contains hereditary material (like DNA-carrying the information for protein synthesis). DNA is bound up with a histone protein to form chromatin.Contains one or more nucleoli-where ribosome submits, ribosomal RNA and transfer RNA are manufactured. Surrounded by double membrane, crossed by a number of nuclear pores. Usually one nucleus per cell BUT may be many in very large cells like skeletal muscles

Question 2

what does DNA carry the information for

Answer 2

protein synthesis

Question 3

what is DNA bound up by

Answer 3

histone protein to form chromatin

Question 4

what three things are manufactured in the nucleoli>

Answer 4

ribosome subunits: ribosomal RNA and transfer RNA are manufactured

Question 5

what type of cells may have many nucleus’

Answer 5

a striated (skeletal) muscle

Question 6

Mitochondrion-pl. mitochondria

Answer 6

Site of aerobic respiration. Highly folded inner membrane which supports the proteins of the electron transport chain responsible for the synthesis of ATP by oxidative phosphorylation. These organelles are abundant in cells which are physically (skeletal muscle) and metabolically (hepatocytes) active.

Question 7

what mainly happens here

Answer 7

it is the site of aerobic respiration

Question 8

what do mitochondria have

Answer 8

a tightly folded inner membrane

Question 9

why does it have a tightly folded inner membrane

Answer 9

to support the proteins of the electron transport chain responsible for the synthesis of ATP by oxidative phosphorylation

Question 10

where are these organelles most abundant

Answer 10

in cells which are physically (skeletal muscle) and metabolically (hepatocytes) active

Question 11

cytoplasm

Answer 11

mainly water-with solutes including glucose, proteins and ions. Supported by the CYTOSKELETON, made up of microtubles and microfilaments

Question 12

what is cytoplasm mainly made of

Answer 12

water

Question 13

what is dissolved in the water

Answer 13

glucose, proteins and ions

Question 14

what is cytoplasm supported by

Answer 14

CYTOSKELETON-made up of microtubles and microfilaments

Question 15

Free ribosomes

Answer 15

site of protein synthesis, mostly for proteins destined for intracellular use. there may be 50 000 or more in a typical eukaryote cell

Question 16

microvilli

Answer 16

extensions of plasma membrane (cell membrane), increase the surface area of the cell. Commonly abundant in cells with a high absorptive capacity, such as epithelial cells of the small intestine or cells of the first coiled tubule of the nephron. Brush border of the cell

Question 17

where are cells with microvilli most coomon

Answer 17

in cells with high absorptive capacity, such as epithelial cells of the small intestine or cells of the first coiled tubule of the nephron

Question 18

endocytic vesicle

Answer 18

may contain molecules or structures too large to cross the membrane by active transport or diffusion

Question 19

microfilaments

Answer 19

threads of the protein actin. Found in bundles beneath the call surface and play roles in endo- and exocytosis and possibly cell movement

Question 20

Centrioles

Answer 20

a pair of structures, held at right angles to one another, act as organisers of the nuclear spindle in the preparation for the separation of chromosomes or chromatids during nuclear division

Question 21

secretory vesicle

Answer 21

undergoing exocytosis. may be carrying a synthetic product of the cell (such as a protein packaged at the Golgi body) or the product of degradation by lysosomes. Abundant in cells with a high synthetic activity, such as cells of isles of langerhans

Question 22

process in which secretory vesicle is going through

Answer 22

EXOCYTOSIS

Question 23

what packages the synthetic product of the cell

Answer 23

Golgi body

Question 24

smooth endoplasmic reticulum

Answer 24

a series of flattened sacs and sheets that are the site of synthesis of steroids and lipids

Question 25

rough endoplasmic reticulum

Answer 25

so-called because of the many ribosomes attached to its surface. This intracellular system aids cells compartmentalisation and transports proteins synthesised at the ribosomes towards the Golgi body for secretory packing

Question 26

Golgi apparatus

Answer 26

consists of a stack of sacs called CISTERNAE. It modifies a number of cell products delivered to it, often enclosing them in vesicles to be secreted. Such proteins include TRYPSINOGEN, INSULIN AND MUCIN. Also involved in lipid modification in cells of the ileum, and plays a part in the formation of lysosomes.

Question 27

Plasmalemma (cell membrane)

Answer 27

surface of the cell and represent sits contact with the environment. It is differentially permeable and regulates movement of solutes between the cell and its environment.

Question 28

Place in the correct order to show the passage of an amino acid from the cytoplasm a until it is secreted from the cell as a protein

Answer 28

cytoplasm->?->?->?-> protein

Question 29

A group of scientists homogenised tissue before carrying out cell fractionation to isolate an organelle Explain why the scientistshomogenised the tissue?filtered the resulting suspension?kept the suspension ice cold during the process?used isotonic solution during the process?(2)

Answer 29

1.Breaks open cells / disrupts cell membrane / releases cell contents / releases organelles / break up cells2.Removes (cell) debris / complete cells / tissue3.Reduces / prevents enzyme activity4. a.Prevents osmosis / no (net) movement of water / water does not enter organelle / water does not leave organelle;4, b. So organelle / named organelle is not damaged / does not burst / does not shrivel;

Question 30

Name two structures present in an epithelial cell from the small intestine that are not present in a cholera bacterium

Answer 30

Nucleus / nuclear envelope / nuclear membrane / nucleolus;Mitochondrion;(Smooth / rough) ER;Lysosome;Microvillus / brush border;Golgi;Linear / non-circular DNA / chromosome; 80S / denser / heavier / larger ribosomes

Question 31

Give one advantage of using a TEM rather than a SEM.

Answer 31

Higher resolution / higher (maximum) magnification / higher detail (of image);ORAllows internal details / structures within (cells) to be seen / cross section to be taken

Question 32

Give one advantage of using a SEM rather than a TEM.

Answer 32

Thin sections do not need to be prepared / shows surface of specimen / can have 3-D images

Question 33

The epithelial cells that line the small intestine are adapted for the absorption of glucose. Explain how.

Answer 33

1. Microvilli2. Large/increased surface area3. Many mitochondria4. (Mitochondria/respiration) produce ATP / release or provide energy (for active transport)5. Carrier proteins for active transport6. Channel / carrier proteins for facilitated diffusion7. Co-transport of sodium (ions) and glucose or symport / carrier protein for sodium (ions) and glucose8. Membrane-bound enzymes digest disaccharides / produce glucose

Question 34

The scientists used a transmission electron microscope to study the structure of an amoeba. Explain why

Answer 34

1. High/ better resolution2. Shorter wavelength3. To see internal structures/ organelles/named organelles

Question 35

What is the function of the mitochondrion?

Answer 35

(Aerobic) respiration

Question 36

Microfold cells are found in the epithelium of the small intestine. Unlike other epithelial cells in the small intestine, microfold cells do not have adaptations for the absorption of food.Microfold cells help to protect against pathogens that enter the intestine. They have receptor proteins on their cell-surface membranes that bind to antigens on the surface of pathogens. The microfold cells take up the antigens and transport them to cells of the immune system. Antibodies are then produced which give protection against the pathogen.Scientists believe that it may be possible to develop vaccines that make use of microfold cells. These vaccines could be swallowed in tablet form. Use information from the passage and your own knowledge to answer the following questions.Microfold cells do not have adaptations for the absorption of food . A. Give two adaptations that other epithelial cells have for the absorption of foodB. Microfold cells have receptor proteins on their cell-surface membranes that bind to antigens . What is an antigen?

Answer 36

A. 1. Microvilli2. Carrier proteins/co-transport proteins/membrane-bound enzymes3. Many mitochondriaB.Substance that causes an immune response/production of antibodies

Question 37

Microfold cells take up the antigens and transport them to cells of the immune system . Antigens are not able to pass through the cell-surface membranes of other epithelial cells. Suggest two reasons why

Answer 37

1. Not lipid soluble2. Too large (to diffuse through the membrane)3. Antigens do not have the complementary shape/cannot bind to receptor/channel/carrier proteins (in membranes of other epithelial cells)