cell structure Flashcards

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1
Q

what is the main function of a nucleus?

A

controls the activity of a cell

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2
Q

how exactly does a nucleus control the activity in cells?

A

Makes DNA and RNA

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3
Q

what does the nuclear envelope consist of?

*including its functions

A

1-inner membrane
2- outer membrane which has ribosomes
3- nuclear pores to transport substances in and out of the nucleus

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4
Q

what is found in the rough endoplasmic reticulum and as a result what is the main function of RER?

A

ribosomes are found and it is a part of the site of protein synthesis

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5
Q

when proteins are made in the rough endoplasmic reticulum, what does the RER do to it?

A

proteins bud off from the RER in vesicles and are taken to the Golgi apparatus for processing

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6
Q

what is an important protein made by the rough endoplasmic reticulum?

A

lysosomes

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7
Q

what is the specific term for what is contained in lysosome and give 4 examples of them.

A
hydrolytic enzymes(lysozyme enzymes)
1- protease
2- nuclease
3-lipases
4-glucosidases
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8
Q

what are 3 main functions of lysosome

A
1- breakdown of old organelles
2- breakdown macromolecule
3-phagacytosis
* bacterium in vacuole fuse with lysosome to from a vacuole of the bacterium and hydrolytic enzymes
4-autolysis
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9
Q

what does the smooth ER contain?

A

enzymes

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10
Q

what does the enzymes in the smooth ER do?

A
1- lipid synthesis
*fatty acids to lipids
2- detoxification
* enzymes convert harmful substances into water soluble ( lipid insoluble)
3- make steroids
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11
Q

1 example of a lipid and 2 examples of a steroid

A
lipid
-cholesterol
steroids
*hormones
- testosterone
-estrogen
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12
Q

how many subunits are ribosomes made up of?

A

2 being a smaller and a larger unit

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13
Q

what is the main function of ribosome?

A

a site of protein synthesis

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14
Q

what are ribosome made up of?

A

R.RNA and protein

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15
Q

where is the R.RNA made ?

A

nucleolus

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16
Q

what 4 organelle can ribosomes be found at?

A
1- nucleus
* outer membrane of nuclear envelope
2- chloroplast
3- cytoplasm
4- rough endoplasmic reticulum
5- mitochondria
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17
Q

what are the sizes of ribosome in the 4 main areas it can be found at?

A
bacterium,chloroplast and mitochondria
=70S
cytoplasm
=80S
*larger ribosomes
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18
Q

what do mitochondrion and chloroplast have their own of?

A

ribosomes and a circular DNA

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19
Q

what type of membranes do mitochondria’s have?

A

double bound membrane

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20
Q

what is the name of the mitochondrial inner membrane and its function

A

cristae
1-has compartments with different enzymes used in respiration cycle
2- where respiration occurs

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21
Q

What is the inner part of the cristae called and its function?

A

matrix ,where respiration takes place

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22
Q

what are 2 functions of the mitochondria?

A

1- aerobic respiration

2-lipid synthesis

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23
Q

what is the Golgi apparatus know as?

A

the packaging center

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24
Q

what is the function of the Golgi apparatus including the faces involved.

A

used to process and transport molecules such as proteins and lipids by the cis and trans face

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25
Q

what are molecules of the Golgi body transported via?

A

the Golgi vesicle

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26
Q

what are 2 main functions of the Golgi body?

A

1- make lysosomes

2- packing proteins and lipids

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27
Q

what type of layer is the cell membrane?

A

phospholipid Bilayer

28
Q

what is found on the phospholipid bilayer?

A

protein molecules
protein channel
cholesterol

29
Q

what are 3 functions of the cell membrane?

A

1- regulates what enters and leaves the cell
2-acts as a barrier protecting organelles from its outer environment
3- communication via the protein receptors which receives signals by eg;hormones

30
Q

what is the function of the cilia?

A

create beating movement

31
Q

what is the structure and function of microvilli?

A

finger like projections which increase surface area

32
Q

what are 4 structures found in plant cells but not in animal cell?

A

1- chloroplast
2-tonoplast
3- cell wall
4- large vacuole

33
Q

what is cell wall made up of in plants and fungi?

A

in plants=cellulose

in fungi=chitin

34
Q

what is the main function of a cell wall? and how exactly does it do its function?

A

supports the cell by
a- giving its structure
b- preventing a change in the cells shape

35
Q

what is the name of part of the vacuole? and what does it contain

A

cell sap which contains sugar and salts

36
Q

what are 3 functions of the vacuole?

A

1- maintains the cell pressure by pushing cytoplasm against cell wall
2- isolates harmful substances from the rest of plant cell by storing it
3- stores salts and sugar

37
Q

what is the “membrane” surrounding the vacuole besides cell membrane

A

tonoplast

38
Q

what is the function of the tonoplast?

A

creates a barrier between the contents of the vacuole and the cytoplasm

39
Q

what does the chloroplast contain, highlighted in the syllabus?

A

1- small circular DNA

2- ribosomes

40
Q

what is the name of the stacked up structures in chloroplast and what is it made up of ?

A

granum made up of thylakoid membrane

41
Q

what are the stacked up structure in chloroplast connected by?

A

thinner thylakoid membrane named lamella

42
Q

what is the empty space of chloroplast filled up with?

A

stroma

43
Q

what is the main function of the chloroplast?

A

light and non light dependent photosynthesis

44
Q

what is the plasmodesmata

A

structure which connects 2 adjacent cells

45
Q

what are 3 functions of the plasmodesmata?

A

1- allows communication between cells
2- allows exchange of substances between cells
* sucrose
*water
*ions
*amino acid
3- allows exchange between cells without having to pass through the cell membrane or cell wall

46
Q

explain the structure of microtubules

A

1-proteins known as alpha-tubulin and beta-tubulin pair and are called dimer.
2-many dimers join to from a protofilament
3-13 protofilament makes up a microtubule

47
Q

what is a feature of microtubule which relates to its function?

A

dimers are able to be added or removed to make the microtubule longer or shorter

48
Q

explain 3 functions of the microtubule

A

1-mitosis
: used in mitosis in anaphase where the microtubules
become shorter to allow the chromosomes to form
chromatids2- transport in neurons
: the microtubules make a pathway from the cell body
to the synaptic terminal where with the help of
protein substances are moved.

3- make cilia/flagella
: the microtubules are arranged in a specific way to
make the cilia/flagella

49
Q

3 examples of substances which can be transported by microtubules in nerve cells

A
  • protein
  • lipids
  • synaptic vesicle containing neurotransmitter
  • organelles such as mitochondria
50
Q

describe the structure of cilia

A

1- has 2 unattached microtube in the middle
2- 9 groups of paired microtubules form a circle
3-the complete microtubule has 13 protofilament
4- the incomplete microtubule has 10 protofilament
5- the complete microtube contains arms made up of dynein protein

51
Q

describe the structure of centrioles

A
  • made up of microtubules where 3 microtubules{ 1 complete and 2 partial} form a group.
  • a total of 9 groups are found to make up 27 microtubules.
  • these 27 microtubules make up 1 centriole
52
Q

describe a function of microtubules

A

used during mitosis where the centrioles help to anchor the microtubule to align the chromosomes into the center of the cell during the metaphase

53
Q

what are general structures found in plant cells but not animal cell?

A
large vacuole
chloroplast
tonoplast
cell wall
plasmodesmata
54
Q

what are general structures found in animal cell but not plant cell?

A

centrioles, cilia, flagella, microvillus, microtubules

55
Q

what is the stroma and what does it contain

A

the jelly like substance in chloroplast which contains enzymes

56
Q

what are 3 plastids?

A

chloroplast
leucoplast
chromoplast

57
Q

outline the 3 plastids

A

chloroplast- general stuff

chromoplast- contains carotenoid pigments which makes red ,yellow and orange pigments

leucoplast divide into 3

proteinoplast: in seeds, to store proteins
amyloplast: in seeds and roots, to store starch
eliaoplast: found in seeds, to store lipids

58
Q

describe the peroxisome

A

a single membraned organelle containing enzymes used to oxidize and remove toxic waste in cells eg: breakdown of hydrogen peroxide into oxygen and water

59
Q

what are the 3 composition of the cytoskeleton?

A

intermediate filaments
microtubule
microfilaments

60
Q

outline the 3 compositions of the cytoskeleton

A

intermediate filaments -structural proteins

microtubule- forms a transport system for organelles

microfilament- made up of threads of actin and used in muscle contraction and movement

61
Q

what are plastids?

A

plastids are self-reproducing double membraned organelles found in plants

62
Q

describe how a microtubule is formed

A
  • alpha tubulin and beta tubulin form dimers
  • the dimers join end to end to form 1 protofilament
  • 13 of these protofilaments arrange themselves in a ring to form a microtubule
63
Q

what is the centrosome?

A

an area where centrioles can be found 90 degrees to each other

64
Q

what are the differences and similarities of basal body and centrioles

A

similarity
-both have a triplet structure of 9+0

differences

  • centrioles at the centrosome is a microtubule organizing center [involved in replication]
  • basal bodies are microtubule organizing center for cilia and flagella
65
Q

what are the 2 parts which make up a cillia/flagella?

A

1-basal body triplet to organize the microtubule for cilia

2- 9+2 structure of a cilia