ch2 celllular structures

Question 1

nucleus form

Answer 1

bounded by nuclear membrane (double membrane)
mainly contains DNA (also contains RNA and various proteins)

Question 2

nucleus function (nucleolus / nuclear pores / nucleoplasm)

Answer 2

generally: storing genetic material that controls the activities of the cell

nuclear pores: allow genetic material (eg. RNA) to exit
nucleolus: spherical structure found in the cell’s nucleus -> produces and assembles the cell’s ribosomes (therefore helps synthesise proteins)
nucleoplasm: same as cytoplasm

Question 3

cell membrane form

Answer 3

thin / flexible
mainly made up of phospholipids and proteins

Question 4

cell membrane function

Answer 4

separates the cell contents from the outside environment
differentially permeable (controls the movement of substances into and out of the cell)

Question 5

what can pass thru differentially permeable membranes

Answer 5

molecules that can pass thru must contain all the following properties:

small
lipid soluble (non-polar overall charge)
uncharged molecules

eg. vit. A / fatty acids

Question 6

cytoplasm form

Answer 6

jelly-like fluid

Question 7

cytoplasm function

Answer 7

holds many organelles
site for many chemical reactions (eg. condensation / hydrolysis)
allows movement and transport of materials inside the cell

Question 8

cell wall form

Answer 8

present in all plant cells
thick and rigid
made up of cellulose

Question 9

cell wall function

Answer 9

fully permeable
protects / supports / gives shape to the cell

Question 10

rough er form

Answer 10

network of interconnected membrane sacs
continuous with the nuclear membrane
with ribosomes bound to it

Question 11

rough er function

Answer 11

site for the synthesis of proteins (hence are abundant in cells that produce a large amount of proteins)

Question 12

smooth er form / function

Answer 12

no ribosomes bound to it (hence site for the synthesis of lipids, and are abundant in cells that produce a lot of lipids)

Question 13

ribosome form

Answer 13

no membrane
bound to rough ER / lying free in the cytoplasm

Question 14

ribosome function

Answer 14

involved in the synthesis of proteins
when lyring freely, making proteins that need to stay inside the cells
ribosomes on rough ER are responsible for producing proteins that need to be secreted from the cells (eg. enzymes in the pancreas so eg. amylase will be synthesised from the ribosomes and then excreted from the cell)

Question 15

mitochondrion form

Answer 15

bound by double membrane
inner membrane is highly folded inwards into the mitochondrion matrix, to increase the surface for reactions to happen in the inner mitochondrion membrane

Question 16

mitochondrion function

Answer 16

main site of aerobic respiration (which requires oxygen)
abundant in cells that use a lot of energy (chemical energy is stored in food, so we need to release this energy via respiration so it can be converted into energy we can use eg. muscle cells and root air cells, to intake a lot of minerals)

Question 17

chloroplast form

Answer 17

present in green plant cells
contains chlorophyll, a green pigment involved in the process of photosynthesis (which produces glucose, hence:)
starch grains are often present inside

Question 18

chloroplast function

Answer 18

site of photosynthesis

Question 19

vacuole in animal cell form

Answer 19

few and and small in animal cells
fluid filled sacs bound by a single membrane
may contain water, enzymes or food

Question 20

vacuole in plant cells form and function

Answer 20

tend to push many of the organelles towards the edge of the cell
large central vacuole
form
located in the center of the cell
contains cell sap, which contains water and dissolved substances
when the large central vacuole is full of water
cells become turgid and press against each other
which provides turgidity (support) to the plant, helping it stay upright

Question 21

what can methylene blue stain

Answer 21

genetic material

Question 22

what does the stain you use depend on

Answer 22

the subcellular structures you want to see inside a cell

Question 23

purpose of staining cells with methylene blue

Answer 23

methylene blue will stain the ox corneal cells to make some subcellular structures of the cells (especially the nucleus more visible)

Question 24

why dont some cells need to be stained

Answer 24

some cells don’t need to be stained because they already have pigments on their structure (ie. naturally pigmented) allowing the cells to already be visible without being stained (same for hydrilla)

Question 25

eukaryotic cells feature

Answer 25

eukaryotes can be multicellular or unicellular (eg, amoeba)

Question 26

prokaryotic cells form and function

Answer 26

smaller, has no true nucleus cell wall (present in most prokaryotic cells, does not contain cellulose) cell membrane (present in all prokaryotic cells, its structure and function are similar to those in eukaryotic cells, also differentially permeable) cytoplasm (does not contain membrane-bound organelles, DNA lying free within it) ribosomes (lying free in the cytoplasm, different from those in the eukaryotic cells, involved in protein synthesis) also structurally different from those in the eukaryotic cells, the function is the same (70S ribosomes, whereas those in eukaryotic cells is 80S) nucleoid (made up of a single circular strand of DNA (naked)) all prokaryotes are unicellular

Question 27

levels of body organisation

Answer 27

cells -(similar cells are grouped tgt)> tissue -(different tissues are grouped tgt)> organ -(diff organs work tgt)> system -(diff systems work tgt) > organism

Question 28

why is iodine solution used to stain banana cells?

Answer 28

the iodine solution will stain the banana cells to make some subcellular structures of the cells more visible / increase colour contrast between subcellular structures this is because banana cells contain many starch grains iodine solution turns from reddish brown to blue black in the presence of starch, allowing the starch grains to be visible by their blue black colour

Question 29

why is iodine solution used for onion epidermal cells?

Answer 29

the onion epidermal cells contain little starch grains iodine solution turns from reddish brown or blue black in the presence of starch

Question 30

how does vitamin b move across the cell membrane

Answer 30

as vitamin B is water soluble, small, polar repelled by the hydrophobic core of the phospholipid bilayer carrier protein / channel proteins provides a hydrophilic pathway for vitamin B to be transported across the cell membrane

Question 31

cell theory

Answer 31

all organisms are made up of one or more cells the cell is the basic unit of life all cells come from pre-existing cells

Question 32

exceptions to the cell theory: skeletal muscle

Answer 32

some tissues and organisms are not made of typical cells eg. skeletal muscle, where the cell is very large and contains a lot of nuclei -> made up of muscle fibres, much larger than other cells and contains many nuclei

Question 33

exceptions to the cell theory: giant algae acetabularia

Answer 33

eg. giant algae acetabularia, can be very large can grow up to 10cm, but is a cell (containing different components eg. cap / stalk / nucleus) with a single nucleus -> shows how large organisms are not automatically multicellular (but usually this is because there is not enough genetic material to control its functions)