organisation of cells

Question 1

what is a cell?

Answer 1

smallest part of an organism that retains characteristics of the entire organism
is the place where metabolic processes occur that keep the organism alive

Question 2

4 examples of tissues
where can they be found?

Answer 2

epithelium - skin, lining of GI tract
muscle - skeletal, smooth, cardiac
nervous
connective - tendons, ligaments, fats, blood, bones

Question 3

what is the simplest form of a cell?

Answer 3

prokaryotes
eg. archaea, bacteria

Question 4

where is DNA in prokaryotic cells?

Answer 4

free floating within the cell cytoplasm

Question 5

where is DNA in eukaryotic cells?

Answer 5

bound inside a nucleus

Question 6

organelles are only present in which type of cell?

Answer 6

eukaryotic

Question 7

3 components of a typical animal cell

Answer 7

plasma membrane
cytoplasm
nucleus

Question 8

function of plasma membrane

Answer 8

separates internal conditions from external conditions
contains protein channels, carriers and pumps for selective permeability
contains cell adhesion molecules (CAMs)

Question 9

what is the role of CAMs?

Answer 9

to attach cells to each other

Question 10

what does selective permeability allow?

Answer 10

the maintenance of membrane potential - the charge difference across the plasma membrane

Question 11

define ion

Answer 11

atom/ molecule with a net electric charge due to the loss or gain of electron(s)

Question 12

2 components of cell cytoplasm:

Answer 12

cytosol and organelles

Question 13

define cytosol

Answer 13

the fluid part of the cytoplasm

Question 14

what does the cytosol contain?
3 examples

Answer 14

proteins and dissolved substances
eg. ions
cytoskeleton
cytoplasmic inclusion eg. lipid droplets or pigments (melanin)

Question 15

3 functions of cytoskeleton

Answer 15

support the cell and holds the nucleus and other organelles in place
movement
transport substances

Question 16

what are the 3 groups of proteins in the cytoskeleton?
example

Answer 16

microtubule - for cell structure - made from tubulin and stiffer than actin filaments eg. flagella, cilia
microfilament - highly organised eg. muscle cells (biggest)
intermediate filament (found in motile organisms and cell division) - flexible but resist strain eg. skin cells

Question 17

function of the nucleus

Answer 17

contains all the cell’s chromosomes which encodes genetic material
has nuclear pores to allow RNA, ribosomes and macromolecules to move between the nucleus and cytoplasm

Question 18

function of mitochondria

Answer 18

provides energy for the cell in the form of ATP

Question 19

5 components of mitochondria

Answer 19

smooth outer membrane
intermembranous space
inner membrane folded into cristae
matrix
circular chromosome

Question 20

define chromatin

Answer 20

delicate filaments found in the nucleus that are formed from dispersed chromosomes

Question 21

what happens to chromatin during cell division?

Answer 21

becomes densely coiled forming chromosomes

Question 22

during transcription, the enzyme … uses DNA as a template to produce a … …

Answer 22

RNA polymerase
pre-mRNA transcript

Question 23

the pre-mRNA is … to form a … mRNA molecule that can be … to build the protein molecule encoded by the original gene

Answer 23

processed
mature
translated

Question 24

the nucleolus forms to …

Answer 24

maximise interactions between specific DNAs, RNAs and proteins

Question 25

active cells have a ... nucleolus

Answer 25

big

Question 26

inactive cells have ... nucleolus

Answer 26

no

Question 27

function of ribosomes

Answer 27

sites of protein synthesis for inside the cell

Question 28

what do ribosomes consist of?

Answer 28

ribosomal RNA (rRNA) and proteins has a large subunit and a small subunit

Question 29

function of ribosomes on the rough endoplasmic reticulum

Answer 29

produce the proteins that are packaged and secreted to be incorporated into the plasma membrane and within lysosomes

Question 30

function of rough endoplasmic reticulum

Answer 30

modifies proteins for secretion

Question 31

function of smooth endoplasmic reticulum

Answer 31

lipid production (eg. membrane phospholipids) and carb metabolism processes proteins - modifies drugs or stores calcium ions (in muscles)

Question 32

function of golgi apparatus

Answer 32

sorts, packages and transports cell products

Question 33

3 important roles of golgi apparatus:

Answer 33

modification of macromolecules proteolysis of peptides into active forms sorting of different macromolecules into specific membrane-bound vesicles

Question 34

how does the golgi apparatus modify macromolecules?

Answer 34

by the addition of sugars to form oligosaccharides

Question 35

what are the 3 functional components of the golgi?

Answer 35

cis face medial golgi trans-golgi network

Question 36

function of vesicles

Answer 36

transport or store material allow the exchange of cell membrane between different cell compartments

Question 37

what are the main types of vesicles? (5)

Answer 37

cell surface-derived endocytotic (pino/ phagocytotic) golgi-derived transport and secretory vesicles ER-derived transport vesicles lysosomes peroxisomes

Question 38

function of lysosomes

Answer 38

transport digestive enzymes digest microbes, worn out cellular components or cells

Question 39

what are the 3 main types of cell-cell connections?

Answer 39

tight junctions desmosomes gap junctions

Question 40

how do tight junctions join cells together? example

Answer 40

form a seal that is so strong not even ions can pass across eg. blood vessels, kidneys

Question 41

how do desmosomes join cells together? example

Answer 41

connect the intermediate filament networks of adjacent cells eg. skin, intestines

Question 42

how do gap junctions join 2 cells?

Answer 42

allow direct cell-cell communication and selective diffusion of molecules eg. heart cardiac muscle - to contract at the same time

Question 43

intermediate filaments provide ... support especially for ... ... of the cell

Answer 43

structural mechanical resistance

Question 44

are intermediate filaments directly involved in cell movements?

Answer 44

no

Question 45

what are intermediate filaments made from?

Answer 45

lots of different types of proteins

Question 46

what are actin microfilaments/ microfilaments made from? what do they form?

Answer 46

actin molecules they form bundles, sheets or networks

Question 47

what are microtubules made from?

Answer 47

alpha and beta tubulin

Question 48

what are microtubules responsible for in the cell?

Answer 48

mitotic spindle, cilia and flagella

Question 49

4 functions of microtubules

Answer 49

mitotic spindle, cilia, flagella provide structure and support to the cytoplasm transport intercellular material by providing tracks for organelles and chromosome movement maintain cell's polarity - filaments have + and - ends

Question 50

3 examples of microtubules

Answer 50

kinesins myosins dyneins

Question 51

where do basal bodies occur?

Answer 51

in ciliated or flagellated cells

Question 52

what do basal bodies and centrioles have in common?

Answer 52

they have the same structure

Question 53

where do centrioles occur?

Answer 53

in the centrosome of cell involved in mitotic division

Question 54

define centrosome

Answer 54

organelle made of 2 centrioles

Question 55

define cilia example of where they are

Answer 55

small and numerous projections on cell surfaces that 'beat' in a co-ordinated power stroke vs recovery stroke (active movement) eg. respiratory tract, female reproductive tract

Question 56

define flagella

Answer 56

larger singular version of cilia that moves the entire cell movement is corkscrew

Question 57

where is the energy for sperm motility derived from?

Answer 57

metabolism of fructose in seminal fluid

Question 58

where are the mitochondria located in sperm?

Answer 58

their midpiece

Question 59

cilia and flagella are ... projections that grow from ... that have moved to the cell membrane

Answer 59

microtubule-based centrioles