Human Biology Instructor Terry Wiseth CELLFUNCTION

Human BiologyHuman Biology

Instructor Terry Wiseth

CELLCELLFUNCTIOFUNCTIO

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CELL DIVISIONCELL DIVISIONthe process of cell

division is essential to the growth and development of all organisms

growth and tissue repair are common occurrences

abnormal cell division is commonly called cancer

DNA DNA REPLICATIONREPLICATION

parent cells must provide daughter cells with hereditary instructions and enough cytoplasmic machinery to start up with their own operation

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DNA DNA REPLICATIONREPLICATION

Cells divide DNA by:1) Mitosis

Occurs in somatic cellsMost of the cells of the body

2) MeiosisOccurs in germ cells

Sperm and egg cells

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CHROMOSOMECHROMOSOMESS

Chromosomes are the genetic material found inside the nucleus of the cell

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Consist of condensed DNA and proteinsDNA controls protein synthesis

Controls the appearance of characters and metabolic activities of an organism

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CHROMOSOMECHROMOSOME

DNA loops

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Each species has a fixed number of chromosomes in the nucleus of each of its cells

Chromosomes always exist in pairs in the body cells

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SOMATIC SOMATIC CELLSCELLSsomatic cells in each species of

organism will have the same number of chromosomes specific to that species

ex: humans = 46 gorillas = 48 pea plant = 14

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CELL CYCLECELL CYCLE

Mitosis M

Gap phase 1 G1

Synthesis phase S

Gap phase 2 G2

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M (M (mitosismitosis))

nuclear division

cytoplasmic division

GG1 1 ( (gap 1gap 1))

interval before the onset of DNA replication

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S (S (synthesissynthesis))

replication of DNA

GG2 2 ( (gap 2gap 2))

interval between completion of DNA replication and the onset of mitosis

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INTERPHASEINTERPHASE

usually the longest phase of the cell cycle

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INTERPHASEINTERPHASEconsists of the G1,S, and G2 phases of

the cell cycle

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1) the cell increases in mass

2) chromosomes cannot be seen

3) chromosomes are duplicated

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STAGES OF STAGES OF MITOSISMITOSIS

Prophase

Metaphase

Anaphase

Telophase

Interphase 19 hrs

Mitosis 1 hr

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PROPHASEPROPHASE

1) chromosomes start condensingchromatids twist and fold on one

another2) spindle fibers begin to form

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PROPHASEPROPHASE

3) centrioles are duplicated and begin to migrate to opposite polescentrioles later give rise to cilia and

flagella

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PROPHASEPROPHASE

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PROPHASEPROPHASE

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METAPHASEMETAPHASE

1) nuclear membrane disappears2) spindle fibers attach to

chromosome centromeres

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METAPHASEMETAPHASE3) spindle fibers from opposite poles

“pull” on the chromosomes orientating them at the equator

4) chromosomes become aligned at the cell equator

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METAPHASEMETAPHASE

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METAPHASEMETAPHASE

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ANAPHASEANAPHASE

1) the two sister chromatids of each chromosome are separated

2) chromatids move to opposite poles

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ANAPHASEANAPHASE

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TELOPHASETELOPHASE

1) the daughter chromosomes arrive at opposite poles

2) chromosomes begin to unwind and decondense to a threadlike DNA molecule

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TELOPHASETELOPHASE

3) nuclear membranes form, enclosing the DNA

4) each new daughter cell has the same number of chromosomes as the parent cell

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TELOPHASETELOPHASE

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DIVISION OF DIVISION OF THE THE

CYTOPLASMCYTOPLASMthe cytoplasm divides during

Telophasecytokinesis- cytoplasmic division

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DIVISION OF THE DIVISION OF THE CYTOPLASMCYTOPLASM

animal cells “pinch in two” by a process called cleavage

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DIVISION OF DIVISION OF THE THE

CYTOPLASMCYTOPLASMAbnormal cell division at this point can lead to physical deformities

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METABOLISMMETABOLISMMetabolism - the capacity to acquire

energy and use it to build, store, break apart and eliminate substances in controlled ways

Energy - the capacity to make things happen

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METABOLISMMETABOLISMcells secure, use and lose energy

cells cannot create energycells must get energy from

somewhere else

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METABOLISMMETABOLISM

Most energy available for energy conversion is stored in covalentcovalent bondsbondsglucose, starch, glycogen and fatty

acids are rich in covalent bondsWhen molecules are

broken apart there isa controlled releaseof energy which isavailable to makethings happen

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METABOLISMMETABOLISM

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CHEMICALCHEMICAL REACTIONSREACTIONS

Many reactions in the cell result in the production of ATP or the use of ATPex: Cellular respiration

CC66HH1212OO66 + O + O22 CO CO22 + H + H22OO

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REACTANTS REACTANTS & &

PRODUCTSPRODUCTS

reactants products or

products reactants

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METABOLIC METABOLIC PATHWAYSPATHWAYS

Orderly sequence of reactions with specific enzymes acting at each step

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REACTION REACTION SEQUENCESSEQUENCES

If the sequence is interrupted the pathway does not continue and by-products begin to accumulate

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BIOSYNTHETIC BIOSYNTHETIC PATHWAYPATHWAY

BiosyntheticBiosynthetic (anabolism) (anabolism) - small molecules are assembled into large molecules of higher energy content

Requires the input or use of ATP

ex: amino acids proteins

fatty acids lipids

glucose starch

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BIODEGRADATIVE BIODEGRADATIVE PATHWAYPATHWAY

BiodegradativeBiodegradative (catabolism) (catabolism) - large molecules are broken down to smaller molecules of lower energy contentex: starch glucose protein amino acids lipids fatty acids

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ENZYMES ENZYMES PROPERTIESPROPERTIES

Able to speed up reactionsspeed up reactions (million fold)described as catalytic molecules

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Enzymes function best within a certain temperature rangetemperature rangeEnzymes lose their 3-dimensional

shape when exposed to high heatex: human cell death - 112 degrees F

ex: Siamese cat – coloring pattern

EFFECTS OF TEMPERATURE EFFECTS OF TEMPERATURE ON ENZYME ACTIVITYON ENZYME ACTIVITY

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Siamese cat-- ears and paws are the darkest part of the bodyHeat sensitive enzyme is less active

in warmer regions of the bodyEnzyme influences higher melanin

production

EFFECTS OF TEMPERATURE EFFECTS OF TEMPERATURE ON ENZYME ACTIVITYON ENZYME ACTIVITY

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EFFECTS OF pH ON EFFECTS OF pH ON ENZYME ACTIVITYENZYME ACTIVITY

Enzymes function best within a certain pH rangepH rangemost function best at pH=7 (neutral)

exception: pepsinpepsin (a stomach cell enzyme) works best at low pH

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ATPATPATP is the energy

currency of the cellThe breakdown of

organic molecules by the cell releases energy which is converted to units of ATP energy

ATP energy is then utilized by the cell to perform a multitude of cell functions

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PATHWAYS LEADING TO ATP PATHWAYS LEADING TO ATP FORMATIONFORMATION

1) Aerobic respiration1) Aerobic respiration2) Anaerobic respiration

Glucose

CO2 + H2O

O2

+ ATP

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1) Aerobic respiration

2) Anaerobic respiration2) Anaerobic respiration

Glucose Pyruvat

e+

ATP

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1) Aerobic respiration2) Anaerobic respiration

Glucose Pyruvat

e

CO2 + H2O

O2

+ ATP

+ ATP

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1) Aerobic respirationrequires oxygenmost cells are able

to perform

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2) Anaerobic respirationdoes not require oxygen

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The amount of ATP energy produced by respiration variesAerobic respirationAerobic respiration

yields 36 ATP36 ATP from1 glucose

Anaerobic respirationAnaerobic respirationyields only 2 ATP2 ATPfrom 1 glucose

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AEROBIC AEROBIC RESPIRATIONRESPIRATION

C6H12O6 + 6O2 6CO2 + 6H2O + ATP energy

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ALTERNATIVE ENERGY ALTERNATIVE ENERGY SOURCES IN THE HUMAN SOURCES IN THE HUMAN

BODYBODY1) Carbohydrates

2) Fats

3) Proteins

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ENERGY SOURCESENERGY SOURCES

very little energy is stored as glucose by the body

Fats-------------------- 78%

Proteins-------------- 21%

Carbohydrates---- 1%

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CELL CELL FUNCTIONFUNCTION

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Human Biology Instructor Terry Wiseth CELLFUNCTION