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cell Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

what is a cell

A

the cell is the fundamental structural and functional unit of all living beings, it is the smallest part of the body of an organism which is capable of independent existence and of performing the essential functions of life

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2
Q

after how many days does a red blood cell die

A

about 120 days

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3
Q

what does cell theory state

A

the cell is the smallest unit of structure of all living things, the cell is the unit of function of all living beings, all cells arise from pre-existing cells

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4
Q

what are single celled organisms

A

many small plants and animals are made up of just one cell

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5
Q

give examples of single-celled organisms

A

bacteria, yeast, amoeba

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6
Q

what are few-celled organisms

A

some very small planta and animals are made up of a relatively fewer number of cells- just a few hundred or a few thousand cells

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7
Q

give examples of few-celled organisms

A

spirogyra, volvox

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8
Q

what are multi-celled organisms

A

most plants and animals we see around us including ourselves, are made up of millions and billions of cells

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9
Q

give examples of multi-celled organisms

A

human beings, mango trees

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10
Q

how many cells are in the human body

A

37.2 trillion cells

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11
Q

how many nerve cells are in the human brain

A

100 billion

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12
Q

how many red blood cells per cubic milimetre of blood

A

4-6 million

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13
Q

how many wbc per cubic milimetre of blood

A

7000

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14
Q

what is the smallest cell and its size

A

bacteria (0.3- 5.0 micrometre)

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15
Q

what is the smallest cell in the human body and its size

A

red blood cells (around 7 micrometre)

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16
Q

what are the longest cells

A

nerve cell, extends from tip of finger to the spinal cord

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17
Q

what are the largest cells

A

ostrich egg (before development begins in it) is the largest single cell of the living world today.

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18
Q

why do cells generally remain small

A

this is because
. Different regions of a call can communicate with each other rapidly for the cell to function effectively
. Cells have a large surface area/volume ratio for greater diffusion of substances in and out of the cell

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19
Q

why do cells have a larger surface area relative to volume of the cell

A

they have this to ensure greater diffusion of
.nutrients into the cell
.metabolic wastes from the interior to the outside of the cell
.respiratory gases i.e oxygen into the cell and carbon dioxide out of the cell
.any damage to the cell can be easily repaired

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20
Q

why do cells vary in shape

A

to fit the function it performs

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21
Q

why are human red blood cells circular and biconcave

A

to pass through narrow capillaries and transport oxygen

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22
Q

why are white blood cells amoeboid

A

so they can squeeze out through capillary walls

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23
Q

why are nerve cells long

A

to conduct impulses from distant parts of the brain to the body and vice versa

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24
Q

why are muscle cells long and contractile

A

to pull or squeeze the parts

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25
Q

why are guard cells of stomatal pore in the leaves bean shaped

A

to open and close the pore

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26
Q

what is a generalised cell

A

It is a basic structural plan shown in all cells, it consists of 3 essential parts
.cell membrane (plasma membrane)
.nucleus
.cytoplasm

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27
Q

what are organelles

A

cell organelles are parts of cell which have a definite shape, definite structure and a definite function

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28
Q

what are parts of plant and animal cells that are living and not in cytoplasm or nucleus

A

cell membrane

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29
Q

what are parts of plant and animal cells that are non living and not in cytoplasm or nucleus

A

cell wall

30
Q

what are parts of plant and animal cells that are living and in the cytoplasm

A

endoplasmic reticulum, mitochondria, golgi apparatus, ribosomes, lysosomes, centrosome, plastids

31
Q

what are parts of plant and animal cells that are non living and in the cytoplasm

A

granules, vacuoles, fat droplets

32
Q

what are parts of plant and animal cells that are living and in the nucleus

A

nuclear membrane, nucleoli, chromatin fibres

33
Q

what are parts of plant and animal cells that are non living and in the nucleus

A

nucleoplasm

34
Q

what are the characteristics of the cell wall

A

outermost in plant cells, non living and rigid, freely permeable, mainly composed of cellulose

35
Q

what are the functions of cell walls

A

gives rigidity and shape to the plant cell, allows substances in solution to enter and leave the cell without any hindrance, provides protection

36
Q

what are characteristics of plasma membrance

A

outermost in animal cells, lies next to cell wall in plant cells, very thin, flexible, living membrane, possesses fine pores, semi-permeable, made up of lipoproteins

37
Q

what are functions of plasma membrance

A

seperates content of cell from its surroundings, regulates the entry of certain solutes and ions, maintains shape of the cell in animal cells

38
Q

characteristics of cytoplasm

A

all the parts together inside the plasma membrane excluding nucleus, contains a mixture of water and soluble inorganic and organic compounds and various organelles

39
Q

functions of cytoplasm

A

different organelles contained in it perform different functions, all metabolic activities occur in it, medium for initial steps of respiration (production of pyruvic acid)

40
Q

characteristics of endoplasmic reticulum

A

irregular network of double-membraned tubules, it is continuous with the plasma membrane on the outside and the nuclear membrane on the inside, may be smooth or rough

41
Q

functions of endoplasmic reticulum

A

supportive framework for the cell, synthesis and transport of proteins and fats

42
Q

mitochondria characteristics

A

various shapes but usually sausage-like, double walled; inner wall thrown into folds (cristae), have their own dna containing several genes, also contain their own ribosomes

43
Q

mitochondria functions

A

release of energy from pyruvic acid produced in cytoplasm in the form of ATP, seat of cellular aerobic respiration and stores energy, synthesis of respiratory enzymes.

44
Q

list cell jobs

A

gas exchange, make energy, build molecules, waste removal, homeostasis, build more cells, respond to external environment

45
Q

what is the cell size of most bacteria

A

1-10 microns

46
Q

what is the cell size of eukaryotic cells

A

10-100 microns

47
Q

golgi apparatus and dictyosome characteristics

A

stacks of flattened membrane sacs, consists of tubules (cisternae), vesicles and vacuoles

48
Q

golgi apparatus and dictyosome functions

A

synthesis and secretion of enzymes, hormonest etc., formation of acrosome of sperm (only in animals and human beings)

49
Q

ribosomes characteristics

A

small granules either scattered in the cytoplasm or attached to the outside of the endoplasmic reticulum, single walled dense, spherical bodies, composed mainly of RNA

50
Q

ribosomes functions

A

protein synthesis

51
Q

lysosomes characteristics

A

membranous sacs budded off from golgi bodies, contain 40 different types of enzymes

52
Q

lysosomes functions

A

intracellular digestion, destroy foreign substances, when cell is old or injured, these rapidly destroy organelles (hence called suicide bags), digest cartilages during formation of bones

53
Q

centrosome characteristics

A

a region surrounding the centrioles, located near the nucleus
contains one or 2 centrioles
centrioles are surrounded by radiating microtubules to form a “star” (aster) during cell division

54
Q

centrosome functions

A

initiates and regulates cell division, forms spindle fibres, with help of asters

55
Q

plastid characteristics

A

several kinds, most common ones are chloroplasts containing the green pigment chlorophyll
double membraned, proteinaceous matrix, contain DNA
disc like structures called thylakoids contain chlorophyll

56
Q

plastid functions

A

chromoplasts impart colour to flowers and fruits- (xanthophyll: yellow, carotene: orange, red which help in pollination of the flower and dispersal of seeds
chloroplasts (green) trap solar energy for photosynthesis contain the pigment chlorophyll
leucoplast stores starch

57
Q

nucleus structure

A

largest cell organelle
mostly spherical and dense
nuclear membrane with pores to allow substances to enter and leave
contains network of thread-like structures called chromatin fibres which contain DNA

58
Q

nucleus functions

A 
regulates cell functions
if removed, the cell dies
contains chromosomes (bearer of genes that control hereditary characters)
59
Q

nucleolus characteristics

A

one or more round-shaped substructures present inside the nucleus

60
Q

nucleolus functions

A

produces ribosomes
participates in protein synthesis by forming and storing RNA
dictates ribosomes to synthesise proteins

61
Q

chromatin fibres structure

A

the network in resting stage of the nucleus condenses into chromosomes during cell division
made up of dna threads

62
Q

chromatin fibres function

A

chromosomes carry hereditary information or the genes from parents to offsprings

63
Q

vacuoles structure

A

clear spaces with water or other substances in solution.
plant cells have larger vacuoles while animal cells have smaller ones
covered by a covering called tonoplast

64
Q

vacuoles function

A

store water and other substances like food and waste products
give turgidity to the plant cells by pressing against the cell wall
contain pigments like anthocyanins etc.

65
Q

granules characteristic

A

small particles, crystals or droplets

66
Q

granules functions

A

store starch (in plant cells), glycogen (in animal cells) and fat containing granules which serve as food for the cell

67
Q

state structural differences between plant cell and animal cell

A

Plant cells have a definite cell wall made up of cellulose while animals cells dont have a cell wall

Centrosome is not present in plant cell but is present in animal cell

Vacuoles are prominent in plant cells while if there are any vacuoles in animal cells they are small and temporary

plant cells usually contain plastids while animal cells dont contain plastids

68
Q

state quantitative differences between plant cell and animal cell

A

plant cells are usually larger with distinct outlines while animal cells are usually smaller with less distinct boundaries

plant cells have a less dense cytoplasm while animal cells have a denser and more granular cytoplasm

Plant cells have only a thin lining of cytoplasm while in animal cells cytoplasm fills almost the entire cell

69
Q

state differences between prokaryotic and eukaryotic cells

A

nucleus is not well defined in prokaryotic cells while eukaryotic cells have well defined nucleus with a nuclear membrane

prokaryotic cells have a single length of only DNA while eukaryotic cells have several lengths of genetic material (chromosomes) containing DNA wound around certain proteins

prokaryotic cells have small ribosomes while eukaryotic cells have larger ribosomes

prokaryotic cells have no other cell organelles while eukaryotic cells have several organelles like mitochondria, endoplasmic reticulum, chloroplasts etc.

70
Q

give examples of prokaryotic cell

A

bacteria, blue green algae (cyanobacteria)

71
Q

give example of eukaryotic cell

A

euglena, amoeba and all plants and animals

72
Q

list cell jobs

A

gas exchange, make energy, build molecules, waste removal, homeostasis, build more cells, respond to external environment

biology (4 decks)

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