Cell Structure

Question 1

Cell

Answer 1

• the basic unit of living
• organisms contains genetic material
• surrounded by cell surface membrane
• cytoplasm containing organelles

Question 2

Nucleus

Answer 2

• large organelle
• present in eukaryotes
• absent in prokaryotes
• contains genetic material ; controls cell activities

Question 3

Eukaryotes

Answer 3

an organism whose cells contain a nucleus and other membrane-bound organelles

Question 4

Prokaryotes

Answer 4

an organism whose cell do not contain a nucleus or other membrane-bound organelles

Question 5

Cell surface membrane

Answer 5

• partially permeable
• controls the exchange of materials between the cell and its environment
• 7nm

Question 6

Chromatin

Answer 6

• materials of which chromosomes are made
• made up of DNA, proteins & small amounts of RNA

Question 7

Chromosome

Answer 7

• a structure made of tightly coiled chromatin
• visible during cell division

Question 8

Nucleolus

Answer 8

manufacture ribosomes using information in its own DNA

Question 9

Protoplasm

Answer 9

all the living material inside a cell ( cytoplasm + nucleus )

Question 10

Cytoplasm

Answer 10

the contents of a cell, excluding the nucleus

Question 11

Mitochondria

Answer 11

organelle i n eukaryotic cells where aerobic respiration takes place

Question 12

Golgi apparatus

Answer 12

consists of a stack of flattened sacs called cisternae

• chemically modifies the molecules it transports

Question 13

Cell wall

Answer 13

• protects cell from mechanical damage
• provides support
• prevents cell from bursting by osmosis in case water potential is higher outside cell
• found in prokaryotic, bacterial & fungal cells

Question 14

Plasmodesmata

Answer 14

• pore-lie structure found in plant cell walls
• allow controlled passage of materials from one cell to another

Question 15

Vacuoles

Answer 15

• storage of biochemicals & waste products

Question 16

Tonoplast

Answer 16

partially permeable membrane surrounding plant vacuoles

Question 17

Chloroplasts

Answer 17

double membrane ( envelope )

Question 18

Grana

Answer 18

stacks of membranes inside a chloroplast

Question 19

Eyepiece graticule

Answer 19

small scale that is placed in a microscope eyepiece

Question 20

Stage micrometer

Answer 20

very small, accurately drawn scale of known dimensions, engraved on a microscope slide

Question 21

Micrographs

Answer 21

a picture taken with the help of a microscope
- photomicrograph = light microscope
- electron micrograph = electron microscope

Question 22

Magnification

Answer 22

the number of times larger the image of an object is compared to the actual size of the object

Question 23

Resolution

Answer 23

• the ability to distinguish between two objects very close together
• higher resolution = more details

Question 24

Microvilli

Answer 24

small, finger-like extensions of a cell to increase its SA for more efficient absorption / secretion

Question 25

Nuclear enmvelope

Answer 25

- two membranes situated close together - surrounding the nucleus - perforated with nuclear pores

Question 26

Nuclear pores

Answer 26

control the exchange of materials -> mRNA between the nucleus & cytoplasm

Question 27

Endoplasmic reticulum

Answer 27

- a network of flattened cisternae in the cytoplasm of eukaryotic cells

Question 28

Ribosomes

Answer 28

protein synthesis - eukaryotic = 80s - prokaryotic = 70s

Question 29

Golgi vesicles

Answer 29

- carry their contents to other parts of the cell - often to the cell surface membrane for secretion

Question 30

Lysosomes

Answer 30

- contains digestive enzymes ( hydrolytic ) - has a variety of destructive functions, such as the removal of old organelles

Question 31

Cristae

Answer 31

fold of the inner membrane of mitochondrial envelope - ATP synthase - electron transport chains associated with aerobic respiration

Question 32

ATP

Answer 32

adenosine triphosphate

Question 33

ADP

Answer 33

adenosine diphosphate

Question 34

Microtubules

Answer 34

- tiny tubes made of protein tubulin - cell support - determines cell shape

Question 35

Centrioles

Answer 35

1 of 2 small cylindrical structures made from microtubules

Question 36

Centrosome

Answer 36

- assembly the microtubules that make up the spindle during nuclear division

Question 37

Cillia

Answer 37

they beat, causing locomotion / movement of fluid across the cell surface

Question 38

Flagellum

Answer 38

they beat, causing locomotion / movement of fluid across the cell surface

Question 39

Thylakoids

Answer 39

a flattened, membrane-bound, fluid-filled sac - site of the light-dependent reactions of photosynthesis

Question 40

Bacterium

Answer 40

single-celled prokaryotes - can form spores

Question 41

Peptidoglycan

Answer 41

also known as murein - makes bacterial wall more rigid

Question 42

Plasmid

Answer 42

smaller circular piece of DNA in a bacterium - often contain genes that provide resistance to antibiotics

Question 43

Viruses

Answer 43

- infectious particle which can only replicate inside living cells - consists of a molecule of DNA / RNA ( genome ) surrounded by a protein coat - an outer lipid envelope may also be present

Question 44

MTOCs

Answer 44

Microtubule Organising Centres

Question 45

Structure of virus

Answer 45

- a self-replicating genome - a protective protein coat ( capsid ) - outer layer made of phospholipid