Unit 1 Chapter 1 Cellular Biology (Weber State)

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1

What are the 8 major cellular functions?

Movement
Conductivity
Metabolic Absorption
Secretion
Excretion
Respiration
Reproduction
Communication

2

Movement

Muscle cells can generate forces that produce motion
EG skeletal and smooth muscle - the contraction of smooth muscle cells surrounding blood vessels changes the diameter of the vessel - contraction of muscles in the bladder when the urge to go to the toilet happens.

3

Conductivity

A response to a stimulus is manifested by a wave of excitation, an electrical potential that passes along the surface of the cell to reach its other parts.
The chief function of nerve cells.

4

Metabolic Absorption

Cells take in and use nutrients. Cells of the kidney and intestine are specialized to carry out absorption.
EG Kidney tubules reabsorb fluids and synthesize proteins. Intestinal epithelial cells reabsorb fluids and synthesize protein enzymes.

5

Secretion

Certain cells (mucous gland cells) can synthesize new substances from substances they absorb and then secrete new substances to serve as needed elsewhere.
EG. Adrenal Glands, testis, ovaries, secrete hormonal steroids.

6

Excretion

All cells rid themselves of waste products resulting in metabolic breakdown of nutrients.
EG Lysosomes within cells contain enzymes that break down or digest large molecules turning them into waste & releasing them from the cell.

7

Respiration

Cells absorb oxygen which is used to transform nutrients into energy in the form of ATP (adenosine triphosphate)
Cellular respiration or oxidation occurs in organelles called mitochondria.

8

Reproduction

Tissue growth occurs as cells enlarge and reproduce themselves. Tissues require maintenance where new cells are produced to replace cells that are lost normally through cellular death (apoptosis)

9

Communication

Critical for cell function and survival. Pancreatic cells secrete and release insulin to tell muscle cells to take up sugar from the blood for energy. Constant communication allows the maintenance of homeostasis.

10

Identify and describe the three parts of a typical eukaryotic cell

Nucleus
Cytoplasm (incl. ribosomes)
Organelles

11

Nucleus

Largest organelle that controls cell activity and stores DNA which carries genetic material and is responsible for cellular reproduction or division

12

Cytoplasm

An aqueous mass that is surrounded by the cell membrane.
Cytosol - aqueous solution making up approx. 1/2 of the cell volume

13

Ribosomes

Synthesize proteins and metabolize fat cells within the cell.
Newly formed ribosomes synthesize a "recognition sequence" or signal like an address on a letter.

14

Endoplasmic Reticulum

Endo = within
Plasma = cytoplasm
Reticulum = network (known as cisternae)
Synthesize proteins and metabolize fat within the cell.
Equate to an assembly line in a manufacturing center.

15

Golgi Apparatus

Holds enzyme systems that assist in completing the cell's metabolic function.

16

Lysosomes

Lyso = dissolution
Soma = body
Contain enzymes that allow cytoplasmic digestion to be completed.

17

Centrioles

One of two tiny structures located in the cytoplasm of animal cells near the nuclear envelope; play a role in cell division.
Organize microtubles of the cytoskeleton to form spindle fibers that help to separate chromosomes during nuclear division.

18

Mitochondria

Mito = thread
Chondros = granule
Powerhouse of the cell. Creates ATP for energy

19

Vacuole

Cell organelle that stores materials such as water, salts, proteins, and carbohydrates
Often used to store materials used in energy production. Also transport materials within the cell and form around particles that enter by endocytosis

20

Cytoskeleton

A network of microtubules, microfilaments, and intermediate filaments that branch throughout the cytoplasm and serve a variety of mechanical and transport functions.

21

Peroxisomes

Single-membrane-bound compartments in the cell responsible for various metabolic functions that involve the transfer of hydrogen from compounds to oxygen, producing H2O2.
Break down fatty acids to be sent to mitochondria for fuel and detoxify alcohol by transferring H from the poison to the oxygen.

22

Vaults

Ribonucleic proteins that float through the cytoplasm; cellular tracking molecules that are bigger than ribosomes; mRNA travels through the vaults from the nuclear pores

23

Cytosol

The soluble portion of the cytoplasm, which includes molecules and small particles, such as ribosomes, but not the organelles covered with membranes

24

Describe the function of the nucleus and the cytoplasmic organelles

Nucleus: stores the cell's hereditary material (DNA) & coordinates activities including growth and reproduction (cell division)

Plasma Membrane: Separates the cell's internal environment from the external environment, has a selective semi-permeable barrier, has a lipid bi-layer, made of 3 types of lipids 1. phospholipids, Cholesterol, and Glycolipids, bi-layer is amphipathic (polar & non polar parts)

Cytoplasmic Organelles - refer to other flashcards.

25

Describe the structure, composition & function of the plasma membrane

Separates the cell's internal environment from the external environment, has a selective semi-permeable barrier, has a lipid bi-layer, made of 3 types of lipids 1. phospholipids, Cholesterol, and Glycolipids, bi-layer is amphipathic (polar & non polar parts)
--Functions -
--Separate the cellular components from the surrounding environment
--Facilitate recognition of the cell
--Provides receptors and enzymes
--Regulate entry and exit of substances
--Provides an anchor for the cytoskeleton

26

Compare and contrast the mechanisms that bind cells together and to the extracellular matrix.

Cells are held by 3 different means
-extracellular matrix
-cell adhesion molecules in the cell's plasma membrane
-specialized cell junctions

27

Extracellular Matrix

An extracellular matrix is a network of non-living tissue which provides support to cells. The extracellular matrix also performs a number of other very specific functions, depending on the types of cells it is associated with, and it takes many forms. The constituent materials in this structure can vary widely; plants, for example, build an extracellular matrix from cellulose, while animals produce extracellular matrices with proteins, minerals, and certain carbohydrates.

The term "extracellular" literally means "outside the cell," which tells you where the extracellular matrix is located. In some cases, the extracellular matrix is actually secreted by the surrounding cells. In bone, for example, a mineralized extracellular matrix is designed to provide support and resist compression. In some cases, the extracellular matrix simply fills up the space between different types of tissue, ensuring that they are kept separate and that their functions are not disturbed.

28

Cell Adhesion Molecules

Specific membrane proteins that allow cells to identify the tissue that they begin with, cells that belong to a specific type of tissue will have cell adhesion molecules that they are complimentary to each other, these proteins will fit into each other and attach the individual cells to other cells in their specific tissue. if one of these cells break away from their tissue, these cell adhesion molecules will evolve into an enzyme that will initiate apoptosis (programmed cell death) in order to prevent a cell from a different tissue type from existing in a tissue where it does not belong

29

Specialized Cell Junctions

Two main functions
1. Hold cells together
2. allow small molecules to pass from cell to cell allowing coordination of the activities of cells that form tissues.
-3 Main Types
1. Desmosomes (adhering junctions or macula adherens)
2. Tight Junctions (impermeable junctions or zonula occludens
3. Gap Junctions (adhering [communicating] junctions)
-Link cytoskeleton of adjacent cells to each other
-Link cytoskeleton to the extracellular matrix

30

What are desmosomes?

1 Act like "spot rivets" that anchor two closely adjacent non-touching cells
2 Most abundant in tissues that are subject to considerable stretching
3 Also use caherin plus intermediate filaments hooking it to the cytoskeleton

31

What are tight junctions?

1 Firmly bond adjacent cells together
2 Seal off the passageway between the two cells
3 Found primarily in sheets of epithelial tissue
4 Prevent undesirable leaks within epithelial sheets
Located in the stomach, intestines, urinary bladder, keep material from leaking out of these organs.

32

What are gap junctions?

1 Small connecting tunnels formed by connexons (pores that allow substances to move <1000 Da between cells)
2 Especially abundant in cardiac and smooth muscle
3 In non-muscle tissues permit unrestricted passage of small nutrient molecules between cells
4 Also serve as method for direct transfer of small signaling molecules from one cell to the next
5 Do not pass proteins, DNA, or RNA
6 Will pass Ca++ and other small HYDROPHILIC ions
7 Cells are electrically charged

33

What are autocrine cells?

Cells that signal themselves (self signaling)
Autocrine signaling is a form of signaling in which a cell secretes a hormone or chemical messenger (called the autocrine agent) that binds to autocrine receptors on the same cell, leading to changes in the cell.

34

What are paracrine cells?

1 Cells that signal their neighbors. Cells can be beside, next to or on top or bottom of.
2 A form of cell signaling in which the target cell is near the signal-releasing cell.
3 Examples of paracrine signaling include responses to allergens, tissue repair, the formation of scar tissue, and blood clotting.
4 Word origin: "para" = alongside of or next to.

35

What are hormonal or neuro-hormonal cells?

Cells that signal distant targets
6 Steps. Each step is a potential point of regulation •Synthesis of the hormones by endocrine or neuroendocrine cells
•Release of the hormones by the endocrine or neuroendocrine cells
•Transport of the hormones to target site through blood
•Detection of the hormones by specific receptors on target cells
○Receptor can be on cell surface or even within cell (steroid receptors, glucocoticoid receptor)
•Change in Cellular Metabolism of target cell. Causes change in what the cell does
•Removal of the Hormone through physical removal, break down or short half-life

36

What is signal transduction?

Signal transduction refers to the specific mechanisms used to transmit signals such as nerve impulses from the outer surfaces of cells to the cell interior.

Takes the chemical and turns it into a change in the bio-pathways

37

Ionotropic Neurotransmitter Receptors

Cause a change in the ionic environment of the neuron

38

Metabotropic Neurotransmitter Receptors

Cause a change in the biochemical (metabolic) environment of the neuron.

39

What are Second Messengers?

Hormones that bind to membrane bound receptors that are not able to exert their effect directly on a cell.

A wide variety of hormones, neurotransmitters and other factors activate these metabotropic receptors.

Two major second messenger pathways:
Calcium [Ca++]
also uses G protein middleman: activates phospholipase C
Cyclic AMP (cAMP) [cyclic adenosine monophosphate]
middleman: G protein that carries GTP or GDP

40

What are the three phases of Food and the Production of cellular energy?

1 Digestion
2 Glycolysis
3 Citric Acid Cycle + oxidative phosphorylation

41

Glycolysis

The breaking down of glucose into 2 molecules of pyruvate.
Takes place in the cytoplasm. It is a part of cell respiration and is the part that is anerobic or doesn't require oxygen.

What goes into glycolysis is c6h12o6 and of course glucose, 2 ATP.

What comes out it 2NADH, 2 PYRUVATE and 4ATP. It is the first step in cell respiration.

42

Citric Acid Cycle

AKA Kreb's Cycle
Cellular respiration is an exergonic reaction, which means it produces energy. It is also a catabolic process - it breaks down polymers into smaller, more manageable pieces. The ultimate goal of cellular respiration is to take carbohydrates, disassemble them into glucose molecules, and then use this glucose to produce energy-rich ATP molecules. The general equation for cellular respiration is: one glucose molecule plus six oxygen molecules produces six carbon dioxide molecules, six water molecules, and approximately 36-38 molecules of ATP.

43

Oxidative Phosphorilation

A process that takes place within the muscle mitochondria if sufficient O2 is present; oxygen is required to support the mitochondrial electron-transport chain and together with chemiosmosis by ATP syntheses , efficiently harnesses energy captured form the breakdown of nutrient molecules and uses it to generate ATP

44

Passive Transport

Movement of substances through a cell membrane without the use of cellular energy; includes diffusion, osmosis, and facilitated diffusion.
This is from HIGH concentration to LOW concentration.

45

Mediated Transport

The process by which transport proteins mediate or assist in the movement of large water soluble molecules, or electrically charged ions/molecules across the plasma membrane.

46

Facilitated Diffusion

The spontaneous passage of molecules and ions, bound to specific carrier proteins, across a biological membrane down their concentration gradients.

Requires the assistance of a carrier molecule because the substance is too polar or too big to pass on its own.

47

Ion Channels

Protein channel in a cell membrane that allows passage of a specific ion down its concentration gradient
REMEMBER non-polar tails of lipid molecules prevent charged molecules like ions from crossing the cell membrane.
Ion channels allow ions to pass DOWN THEIR CONCENTRATION GRADIENT [from high to low concentration areas]
Some are open all the time
Some are gated - they open and close on demand.

48

Active Transport

Requires ATP as an energy source.
The movement of chemical substances, usually across the cell membrane, against a concentration gradient; requires cells to use energy.
Uses preexisting, permanent gradient to drive molecules across the Plasma Membrane.
EG When Na+ is high outside and low inside, the cell wants the Na+ to enter and it moves down the concentration gradient.

49

Endocytosis

The cellular uptake of macromolecules and particulate substances by localized regions of the plasma membrane that surround the substance and pinch off to form an intracellular vesicle.

50

Exocytosis

The process by which a substance is released from the cell through a vesicle that transports the substance to the cell surface and then fuses with the membrane to let the substance out

51

Resting Membrane Potential

High concentration of sodium (Na+) ions outside the cell and a high concentration of anions and potassium (K+) ions inside gives a neuron a Resting Membrane Potential of -70mV. The membrane is polarized.

52

Action Potential

A rapid change in the membrane potential of an excitable cell, caused by stimulus-triggered, selective opening and closing of voltage-sensitive gates in sodium and potassium ion channels.

53

Cell Cycle

The cycle of growth and asexual reproduction of a cell, consisting of interphase (g1, s, g2 cycles) and mytotic phase (mytosis[division of the cell in prophase, prometaphase, metaphase, anaphase, and telophase cycles] & cytokinesis[splitting of the cell])
In g0 the cell does not divide.

54

Mitosis

in eukaryotic cells, a process of cell division that forms two new nuclei, each of which has the same number of chromosomes

55

Growth Factors [Cytokines]

Transmit signals within and between cells
Regulate checkpoints in the cell cycle

56

Platelet-derived growth factor [PDGF]

Stimulates skin cells to divide and heal wounds
Encourages the proliferation of connective tissue

57

Nerve growth factor [NGF]

Encourages proliferation of nerve cells

58

Insulin-like growth factors I & II [IGF I & II]

Works with PDGF to encourage proliferation of fat cells and connective tissue.

59

Erythropoietin

A hormone produced and released by the kidney that stimulates the production of red blood cells by the bone marrow.
Encourages proliferation of red cell precursor cells

60

What are the four types of tissue?

1 Epithelial tissue (skin)
2 Connective tissue
3 Muscular tissue
4 Nervous tissue

61

Epithelial tissue

Made up of closely packed cells in one or more layers. Lines the internal and external body surfaces

62

Connective tissue

Connective tissue is a supportive tissue consisting of a relatively few cells scattered among a great deal of extracellular material (matrix), and includes adipose tissue (fat), bone, cartilage, the dermis of the skin, tendons, ligaments, and blood.

Holds the structure of the body

63

Muscular tissue

Generates the physical force needed to make body structures move and generate body heat
Moves body parts

64

Nervous tissue

Tissue that receives messages from the body's external and internal environment, analyzes the data, and directs the response.
Sensation, information processing, and control of body parts

65

Features of Epithelial Tissue

1)Arranged in sheets of single or multilayer cells.
2) consist of mostly packed cells and no extracellular material.
3) Avascular (no vessels) get the material through diffusion.
4)have good nerve supply.
5)high mitotic rate.
6) Adhere to nearby connective tissue via a thin extracellular layer (basement membrane).
7) they have an apical surface, a basal surface, and a lateral surface.

66

Extracellular Matrix

Contains fibers 1. collagen 2. elastic 3. reticular
An extracellular matrix is a network of non-living tissue which provides support to cells.
The extracellular matrix also performs a number of other very specific functions, depending on the types of cells it is associated with, and it takes many forms. The constituent materials in this structure can vary widely; animals produce extracellular matrices with proteins, minerals, and certain carbohydrates.
Fibroblasts secrete extracellular matrix

67

Skeletal Muscle Tissue

Striated, mostly voluntary (respiratory is involuntary), multi-nucleate (more than one nucleus) so lots of DNA to code for protein synthesis, tendon attaches muscle to bone
Under our voluntary control
moves body at joints
multiple cells fuse to form long muscle fibers so it has multiple, eccentric nuclei. Is controlled by the brain.

68

Cardiac Muscle Tissue

Branching structure, striated, generally uni-nucleate cells that interdigitate at specialized junctions (intercalated discs)
found only in the HEART
involuntary control

69

Smooth Muscle Tissue

No striations and involuntary, found in walls of hollow visceral organs such as the stomach urinary bladder and respiratory packages, forces food and other substances through internal body channels
Single cells
Central nucleus
Arteries, gut tubes

70

Nervous Tissue

Transmit electrical signals from sensory receptors and to effectors (muscles and glands) which control their activity
Located Brain, spinal chord, and nerves
Only tissue in the body that can manipulate electrical charges to receive, process and transmit information.
TWO MAIN TYPES: neurons and glial cells

71

Neurons

Transmit and receive information throughout the nervous system through the conduction of electrical and chemical impulses
Information processing

72

Glial Cells

Supportive cells of nervous system that guide growth of new neurons; forms myelin sheath; holds neuron in place; provides nourishment and removes waste