The Cell Flashcards

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1
Q

What are cells

A

The structural and functional units of an organism
The smallest structure capable of performing all functions necessary to life

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2
Q

What terms describe the amount of cells an organism has

A

Unicellular - one cell

Multicellular - at least 2 cells, can be many many more

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3
Q

What are the three types of cell in nature

A

Prokaryotic : lack a membrane enclosed nucleus. Simple bacteria
Eukaryotic: have a membrane bound nucleus, and organelles. Protists, fungi, plants, animals
Archaeans: posses qualities of both, archaebacteria

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4
Q

What are the three statements of cell theory

A
  • all organisms are made of cells
  • cells are the basic living unit for all life
  • cells come from previous cells
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5
Q

How big are cells

A

Small
Less than 1 mm
Some as small as 1 um (1/1000 mm)

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6
Q

Why do cells need to be small

A

Cells consume food and produce waste, this is relative to cell volume
Cells thus need to take in food and let out waste, this is relative to cell surface area
As a cell becomes bigger the volume increases at a faster rate than surface area
At a certain size the cell would not be able to take in enough food to feed it fast enough, and let out enough waste fast enough

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7
Q

What might cells do to increase surface area

A

The outer membrane might fold and wrinkle to increase surface area without increasing volume

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8
Q

What are the main cells we learn about

A

Eukaryotic cells, they have a nucleus and organelles. And form the base of animals, plants, fungi, and protists

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9
Q

What is the cell membrane

A

A phospholipid bi-layer that is embedded with protein molecules,
Surround the cell and separates the inside of the cell from the out

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10
Q

What fills the inside of the cell

A

A semi fluid medium called cytoplasm,
Composed of water, salts, and dissolved organic molecules

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11
Q

What are cell walls

A

A permeable but protective wall that is around the cell membrane, gives rigidity and protection to certain cells

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12
Q

What types of cell have cell walls

A

Plants cells have 1 cellulose and 1 lignin cell wall

Fungi have cellulose and chitin cell walls

Some algae have cellulose cell walls

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13
Q

What are organelles

A

Well defined sub cellular structures that perform a specific, important function for the cell

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14
Q

What is the nucleus

A

A prominent organelle with a diameter of ~5um
Stores the genetic information of the cell, DNA, and controls cell functions

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15
Q

What is inside the nucleus

A

Chromatin: DNA + Proteins, condenses into chromosomes

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16
Q

What is the semi fluid inside the nucleus

A

Nucleoplasm

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17
Q

What is the nucleolus

A

The area where ribosomal RNA (rRNA) is produced

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18
Q

What is around the nucleus

A

The nuclear envelope

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19
Q

What is attached to the nuclear envelope

A

The rough ER

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20
Q

What are nuclear pores

A

Holes around 100nm that permit bidirectional transport of proteins and ribosome subunits

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21
Q

What do ribosomes do

A

Synthesis proteins using mRNA as a template

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22
Q

What are ribosomes made of

A

Small + large subunits, each is a complex of unique ribosomal RNA and proteins

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23
Q

Where are ribosomes found

A

In the cytoplasm, groups called polyribosomes, and RER

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24
Q

What organelles are in the endomembrane system

A

Nuclear envelope + ER + golgi + vesicles
Does transport and processing of the cell

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25
Q

What is the Endoplasmic Reticulum

A

Complicated system of membranous channels and sacs (flattened vesicles)
Connects to nuclear envelope

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26
Q

What is the rough ER

A

Studded with ribosomes which synthesis proteins
Inside the RER proteins are processed and modified

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27
Q

What is the smooth ER

A

Connected to rough ER, has no ribosomes
Synthesizes phospholipids, producers testosterone, detoxifies drugs, stores calcium ions
Forms vesicles which transport materials to golgi

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28
Q

What is the Golgi apparatus

A

3-20 slightly curved sacs, stacked on top of each other
One side faces nucleus, other faces membrane

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29
Q

What does the Golgi apparatus do

A

Receives proteins + lipid vesicles from ER, as they move through they are modified, repackaged into secretory vesicles
Forms lysosomes

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30
Q

What is secretion

A

Secretory vesicles move from Golgi and release materials outside cell

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31
Q

What are lysosomes

A

Membrane bound vesicles produced by Golgi
Contain hydrolytic digestive enzymes

32
Q

What do lysosomes do

A

Digest food molecules into simpler subunits
White blood cells use them to eat bacteria
Consume food, garbage, and old organelles

33
Q

What are vacuoles

A

Large membranous sacs, larger than vesicles
Store substances like water, sugars, salt, pigment, toxins
Bigger in plant cell

34
Q

What are peroxisomes

A

Similar to lysosomes, membrane bound vesicles that envelope enzymes
Synthesized by cytoplasmic ribosomes and transported by carrier proteins

35
Q

What enzymes are in peroxisomes

A

Enzymes produce H2O2 which is broken down into water + oxygen by another enzyme called catalase
Vary between cells

36
Q

What do chloroplast do

A

Use solar energy to synthesis carbohydrates
6C02 + 6H20 -> C6H12O6 + 6O2

37
Q

What do mitochondria do

A

Brake down carbohydrates while producing ATP
C6H12O6 + 6O2 -> 6CO2 + 6H2O + 38 ATP

38
Q

What is the structure of chloroplasts

A

4-6 um in diameter 1-5 um long
Contains chlorophyll
2 membranes enclose fluid called stroma
Membrane system folds into flattened sacs called thylakoids in stacks called grana

39
Q

What is the structure of mitochondria

A

0.5 - 10 um in diameter 2-5 um long
Double membrane around fluid matrix
Inner membrane folds to form cristea which give more surface area

40
Q

What are the 3 parts of the cytoskeleton

A

Actin filaments (microfilaments)
Intermediate filaments
Microtubules

41
Q

What are microfilaments

A

7nm wide
Long, thing, flexible fibres
Bundles + mesh like networks
2 globular actin monomers twisted around in a helical manner
Form a web, make pseudopods

42
Q

What are intermediate filaments

A

8-11 nm wide
Rope like assembly of fibrous polypeptides that vary between tissue
Support nuclear envelope, membrane, help cell to cell interactions

43
Q

What are microtubules

A

Small, hollow cylinders
25 nm wide, 0.2-25 um long
Made of globular protein tubules of 2 types, 23 rows of tubulin dimes around empty core

44
Q

What are centrioles

A

2 structure found in animal cells
May be involved in microtubules assembly + disassembly
Short cylinders of microtubules that become centrosomes

45
Q

What are centrosomes

A

Structures that manipulate chromosomes during cel division

46
Q

What are cilia and flagella

A

Hair like projections that move cells
Undulate, whip, stiffly or like oats
Cilia are shorter
Membrane bound cylinders of 9 around 2 centre

47
Q

What is the cell membranes purpose

A

To separate the inside of the cell from the out
To regulate entrance and exit of molecules to maintain homeostasis

48
Q

What is the main part of the cell membrane

A

The phospholipid bilayer, a fluid like membrane that can stiffen and strengthen due to cholesterol

49
Q

What are the two types of proteins in a cell membrane

A

Peripheral = one side
Integral proteins = span both sides may only protrude on one though

50
Q

What is the fluid-mosaic model

A

Membrane structure of phospholipids, proteins that can move laterally through them, and steroids

51
Q

What carbs are involved in the cell membrane

A

Glycolipids and glycoproteins
Play roles in cell identification

52
Q

What do peripheral proteins do

A

Play a structural role and help stabilize and shape membrane

53
Q

What are channel proteins

A

Involved in passage of molecules through membrane, have a channel, and possibly a gate

54
Q

What are carrier proteins

A

Combine with substance to move it across the membrane

55
Q

What are cell recognition proteins

A

Glycoproteins help recognize pathogenic invasion to start immune reaction

56
Q

What are receptor proteins

A

Shapes allow specific proteins to bind to it, changing its shape to bring about a cellular response

57
Q

What are enzymatic proteins

A

Carry out metabolic reactions directly

58
Q

How permeable is the cell membrane

A

Selectively permeable, some particles can cross others cannot

59
Q

What is diffusion in cells

A

The passage of small particles and gases through the cell membrane from high to low concentrations passively

60
Q

What factors can affect diffusion

A

Temp, pressure, electrical currents, molecule size

61
Q

What is osmosis

A

The diffusion of water molecules

62
Q

What is osmotic pressure

A

Pressure that developed due to osmosis in a system

63
Q

What is an isotonic solution

A

A solution that has an equal solute/water concentration inside and outside a membrane (cell)

64
Q

What is a hypotonic solution

A

A solution that causes water to move into a cell, making it swell or lyse.
There is less solute concentration out of the cell

65
Q

What are the terms for cell disrupted by hypotonic solutions

A

Cytolysis : disrupted cell
Hemolysis : disrupted red blood cell
Turgor pressure : plant cell that Is swelling but can’t lyse due to rigid cell wall

66
Q

What organisms have to be adapted to withstand hypotonic solutions

A

Those living in fresh water

67
Q

What are hypertonic solutions

A

Cause cell to shrivel / shrink
More solute concentration outside cell
Water moves out of cell

68
Q

What two terms describe the affects of hypertonic solutions to cells

A

Crenation: shriveling of a cell in hypotonic solutions
Phasmolysis: membrane pulls off of cell wall due to crenation in plant cell

69
Q

What types of organisms need to be adapted to hypertonic solutions

A

Marine animals

70
Q

How are molecule transported by carrier proteins

A

A specific molecule / ion bonds to the protein, which then changes shape moving the material across the membrane

71
Q

What is facilitated transport

A

Allows passage of glucose + amino acids, even though they can’t pass through lipids
Passive
Specific proteins

72
Q

What is active transport

A

Opposite to diffusion direction (low to high[])
Needs energy:ATP
Carrier proteins can pump materials across
Sodium potassium pump moved 3 Na then 2 K ions across

73
Q

What is exocytosis

A

A vesicle fused to membrane opening out side the cell to release materials in a process called secretion
Release hormones, neurotransmitters, digestive enzymes

74
Q

What is endocytosis

A

A portion of the cell membrane folds around materials to bring it into the cell in a vesicle
Multiple types

75
Q

What is phagocytosis

A

Large molecules like food particles
Often leads to lysosome digestion materials
Seen on light microscope

76
Q

What is pinocytosis

A

Liquids or small molecules
Happens a lot though you need a e- microscope to see

77
Q

What is receptor mediated endocytosis

A

Pinocytosis but in an area (pit) where receptor proteins bind to specific molecules
Vitamins, peptide hormones, lipoprotein, etc
Effecient, used to transfer materials between cells