cell structure

Question 1

what are cells

Answer 1

-cells are the smallest units of life
-all living things are made up of cells
-all cells come from pre-existing cells

Question 2

what are the two types of cells?

Answer 2

prokaryotic and eukaryotic

Question 3

what are prokaryotic cells?

Answer 3

they do not contain a nucleus or any other membrane-bound organelle. they include two groups: bacteria and archaea

Question 4

what are eukaryotic cells?

Answer 4

they contain membrane-bound organelles including a nucleus. they can be single-celled or multi-celled. e.g. humans, plants, fungi and insects

Question 5

define membrane

Answer 5

a sheet-like structure acting as a boundary or partition

Question 6

define membrane-bound organelles?

Answer 6

organelle with special function that are separated from the rest of a cell by a membrane

Question 7

what are similarities between eukaryotes and prokaryotes?

Answer 7

-dna
-cell membrane
-comes from pre-existing cells
-cytoplasm
-ribosomes
-both are cells

Question 8

differentiate between pro and euk cells

Answer 8

pro: circular dna in nucleoid, no nucleus, simple reproduction process
euk: paired linear dna in nucleus, complex reproduction process like mitosis

Question 9

differentiate between light and electron microscopes

Answer 9

light: colour, can see live specimen, max magnification x2000, lower resolving power
electron: no colour, can’t see live specimen, max magnification x10,000,000, higher resolving power

Question 10

define magnification

Answer 10

appears larger and expressed in the form of x10, x50, calculated with the eyepiece multiplied by the objective lens

Question 11

define microscope

Answer 11

technology that allows us to magnify something to a size greater than we could see with the naked eye

Question 12

what is the function of nucleus?

Answer 12

controls cell activities sending messages

Question 13

what is the function of vacuole?

Answer 13

storage for things like water

Question 14

what is the function of chloroplast?

Answer 14

responsible for photosynthesis = the production of glucose

Question 15

what is the function of cell wall?

Answer 15

holds cell in fixed shape which gives support, protects contents and limits size

Question 16

what is the function of cell membrane?

Answer 16

separates living cell from environment, controls incoming and outgoing substances (selectively permeable), protects cell

Question 17

what is the function of cytoplasm?

Answer 17

carries substances around cell, medium in which things travel

Question 18

what is the function of ribosomes?

Answer 18

where proteins are created living on the ER

Question 19

what is the function of endoplasmic reticulum (ER)?

Answer 19

involved in transport of materials in the cell (proteins) connecting cell membrane with nuclear membrane

Question 20

what is the function of golgi body?

Answer 20

involved in sorting, storing, modification and transport of proteins

Question 21

what is the function of the mitochondria?

Answer 21

release energy, site of respiration

Question 22

what is the structure of the nucleus?

Answer 22

surrounded by double membrane=increase surface area (SA) so more reactions can take place. Pores=letting molecules move in and out, messages for activities

Question 23

what is the structure of the vacuole?

Answer 23

open space allowing more storage for things like water

Question 24

what is the structure of the chloroplast?

Answer 24

grana (stacks of membrane) have large SA to increase rate of photosynthesis

Question 25

what is the structure of the cell wall?

Answer 25

outer most area, surrounds the cell

Question 26

what is the structure of the cell membrane?

Answer 26

pores=letting molecules move in and out

Question 27

what is the structure of the cytoplasm?

Answer 27

jelly-like

Question 28

what is the structure of the ribosomes?

Answer 28

made up of a few parts. lives on the ER

Question 29

what is the structure of the endoplasmic reticulum (ER)?

Answer 29

coming out of the nucleus, rough=with ribosomes, smooth=no ribosomes

Question 30

what is the structure of the golgi body?

Answer 30

made from single membrane with a large SA for synthesising new compounds

Question 31

define fluid mosaic model

Answer 31

current model of membrane structure

Question 32

What features/characteristics are critical to the function of proteins within the cell membrane? how is it maintained?

Answer 32

protein shape is critical to its function, it is maintained by many different chemical changes

Question 33

what leads a protein to denaturation (loss of function)?

Answer 33

changes in temperature, pH, and exposure to chemicals

Question 34

what is the lipids function in the cell membrane

Answer 34

energy stores
components in membrane
lipids are not soluble in water

Question 35

define cell membrane

Answer 35

a selectively permeable barrier. it can be thought of as a gate that opens and shuts rather than a closed wall

Question 36

what is a cell membrane made of?

Answer 36

a double layer of phospholipids (lipids)

Question 37

what is the head of a lipid called and its function

Answer 37

the hydrophilic (water-loving) phosphate heads are positioned facing outwards (towards the cytoplasm on one side and to the outside of the cell on the other) they are attracted to the watery fluids inside and outside cells

Question 38

what is the tail of a lipid called and its function

Answer 38

the hydrophobic (water-hating) lipid tails are positioned inwards (towards each other)

Question 39

where are the proteins in the cell membrane located

Answer 39

they are scattered throughout the lipid, some go all the way through the bilayer to allow materials through, some may be partly embedded in the membrane. some fixed some travelling freely giving the mosaic effect

Question 40

what is the purpose of the fluid mosaic model?

Answer 40

controls the exchange of material between intracellular and extracellular environment of the cell