CELS191 - PROGRESS TEST

CHARACTERISTICS OF LIFE

Cellular organization.

Reproduction.

Metabolism.

Homeostasis.

Heredity.

Response to stimuli.

Growth and development.

Adaptation through evolution.

REQUIREMENTS FOR NATURAL SELECTION

Variation - individuals in a population vary

Inheritance - Parents pass on traits to offspring genetically

Selection - some variants reproduce more than others

Time - Accumulate over generations

3 DOMAINS OF LIFE

Archaea

Bacteria

Eukarya

RELATIONSHIP BETWEEN BUILDING BLOCKS AND HIGHER ORDER STRUCTURES IN CELLS

Building Blocks (low order)

- Amino Acids

- Nucleotides

- Lipids

- Simple Carbs

Macromolecules

- Proteins

- DNA

- RNA

- Complex Carbs

- Lipids

Supramolecular Assemblies

- Membranes

- Ribosomes

- Chromatin

Organelles (high order)

- Nucleus

- Mitochondria

- Golgi Apparatus

- Endoplasmic Reticulum

MAJOR TYPES OF MACROMOLECULES

Carbohydrates

Lipids

Nucleic Acids

Proteins

ROLES OF CARBOHYDRATES

Recognition

Energy

Structure

ROLES OF PROTEINS

Structural

Regulatory

Contractile

Transport

Storage

Protective

Catalytic

Toxic

ROLES OF NUCLEIC ACID

DNA

RNA

ROLES OF LIPIDS

Structural

Regulatory

Energy

IMPORTANCE OF ORGANELLES

Provide special conditions for specific processes.

Keep incompatible processes apart.

Allow specific substances to be concentrated

Form concentration gradients.

Package substances for transport or export.

SUB-CELLULAR COMPONENTS

Endoplasmic Reticulum

Lysosomes

Mitochondria

Nucleus

STRUCTURE OF PLASMA MEMBRANE AND ITS FUNCTION TO CELL SIZE

Semi-permeable barrier

Controls movement of substances in and out of cell

Limits max size of a cell

SIMPLE DIFFUSION (PASSIVE TRANSPORT)

passes directly through the membrane and don't require energy

membrane restricts movement of water soluble/charged molecules.

FACILITATED DIFFUSION

process of diffusion in which hydrophilic molecules pass across the membrane through cell membrane channels

ACTIVE TRANSPORT

Energy-requiring process that moves material across a cell membrane against a concentration gradient

CO-TRANSPORT

Indirect active transport

One substance pumped across membrane

ROLES OF MEMBRANE PROTEINS

Signal Transduction

Cell Recognition

Intercellular Joining

Linking Cytoskeleton and ECM

ENDOMEMBRANE SYSTEM

A membrane interconnected by direct physical contact or transfer by vesicles

ENDOMEMBRANE SYSTEM INCLUDES:

Nuclear envelope

Endoplasmic reticulum

Golgi apparatus

Vesicles

Lysosomes

Vacuoles

Plasma membrane.

FUNCTIONS OF ENDOMEMBRANE SYSTEM

regulates protein traffic and performs metabolic functions in the cell

BULK TRANSPORT PROCESSES

Endocytosis

- Phagocytosis

- Pinocytosis

- Receptor Mediated

Endocytosis

Exocytosis

EXOCYTOSIS

Transports materials out of cell or delivers it to cell surface

CONSTITUTIVE EXOCYTOSIS

Releases ECM proteins

REGULATED EXOCYTOSIS

Releases hormones and neurotransmitters

ENDOCYTOSIS

the cell takes in molecules and particulate matter by forming new vesicles from the plasma membrane

PHAGOCYTOSIS

A type of endocytosis in which a cell engulfs large particles or whole cells

CELL EATING

PINOCYTOSIS

A type of endocytosis in which the cell ingests extracellular fluid and its dissolved solutes.

CELL DRINKING

RECEPTOR-MEDIATED ENDOCYTOSIS

The uptake of bulk quantities of specific substances based on a cell's receptor proteins

ROLE OF LYSOSOMES

Digest and recycle unwanted cellular materials

MAJOR COMPONENT OF CYTOSKELETON

Microtubules

Microfilaments

Intermediate Filaments

HOW MICROTUBULES, MICROFILAMENTS AND INTERMEDIATE FILAMENTS REGULATE CELL SHAPE

Microtubules - resist

Microfilaments - resist tension

Intermediate Filaments - forms relatively permanent cell structure

ALL MAINTAIN CELL SHAPE

IMPORTANCE OF TIGHT JUNCTIONS

Hold neighbouring cells tightly together

Prevent movement of fluid

Form a continuous seal

IMPORTANCE OF DESMOSOMES

Anchoring junction

Provides attachment between sheets of muscle

IMPORTANCE OF GAP JUNCTIONS

A point of cytoplasmic contact between two cells

Allows rapid cell to cell communication

ORIGIN OF EXTRA CELLULAR MATRIX (ECM)

Composed of materials secreted by cells

Most ECM are glycoproteins

STRUCTURE OF PRIMARY PLANT CELL WALL

Most abundant macromolecule on earth

Glucose Polymer

Highly Ordered

Ribbon like structures

FUNCTION OF PRIMARY PLANT CELL WALL

Influences cell morphology

Provides structural support

Prevents excessive water uptake

HOW PRIMARY PLANT CELL WALL IS SYNTHESISED

1. Cellulose microfibrils at plasma membrane

2. Polysaccharides in golgi apparatus transferred to vesicle walls

3. Vesicles fuse to plasma membrane

STRUCTURE OF VACUOLE

An organelle surrounded by single membrane

Highly selective, controlling much of what enters and leaves vacuole

Water moves in vacuole by osmosis

ROLE OF VACUOLE IN MAINTAINING CELL SHAPE

High Concentration of solutes in vacuole which results in water uptake by osmosis.

cell wall limits water uptake and prevents cell bursting

STRUCTURE OF SECONDARY PLANT CELL WALL

Made of many layers

Microfibrils in each layer

FUNCTION OF SECONDARY PLANT CELL WALL

Lignin

- confers strength, regidity of secondary cell wall

Structural Support

PLASMODESMATA

Intercellular connections that enable cell to cell communications

FUNCTION OF PLASMODESMATA

prevents organelle movements and allows free exchange of small molecules

MAJOR ENERGY REQUIREMENTS OF PLANT AND ANIMAL CELLS

Cells need energy for:

Mechanical work

Make new materials

Transport

Maintaining order

BASIC STRUCTURE OF MITOCHONDRION

1-10 micrometres long

Contains mitochondrial DNA and Ribosomes

Has 2 membranes - inner and outer

FUNCTION OF MITOCHONDRION

Site for cellular respiration

CELLULAR COMPARTMENTS IN ENERGY CONVERSION

1. Glycolysis

2. Pyruvate Oxidation and Citric Acid Cycle

3. Oxidative Phosphorylation

- The electron transport chain

- Chemiosmosis

MECHANISM OF ATP SYNTHESIS

The proton gradient across inner membrane powers ATP synthesis

ROLE OF ATM POWERING CELLULAR ACTIVITY

The cell continuously use and regenerates ATP

STRUCTURE OF CHLOROPLAST

Three Membranes

- Inner

- Outer

- Thykaloid

Three Compartments

- Intermembrane Space

- Stroma

- Thylakoid Space

FUNCTION OF CHLOROPLAST

Contains chlorophyll which absorbs light energy for photosynthesis

HOW CELLS CAPTURE LIGHT ENERGY

Light Reactions

- Capture light energy and convert it to chemical energy

TWO STAGES OF PHOTOSYNTHESIS

1. Light reactions

2. Calvin cycle

MAIN INPUTS AND OUTPUTS OF PHOTOSYNTHESIS

Inputs - Light, Water, Carbon

Outputs - Glucose, Oxygen

PROCESS OF ENERGY SUPLLY IN ANIMAL AND PLANT CELLS

Glucose:

- Breakdown glucose to generate energy

ATP:

- generated in both respiration and photosynthesis

- requires proton gradient across membrane in chloroplast and mitochondrion

ORIGIN OF MITOCHONDRIA AND CHLOROPLASTS

Both contain DNA and Ribosomes

Both have inner and outer membrane

STRUCTURE OF NUCLEUS

Composed of two membranes surrounded by nuclear envelope

FUNCTION OF NUCLEUS

Control center of the cell

ROLE OF NUCLEAR PORE COMPLEX IN NUCLEO-CYTOPLASMIC EXCHANGE

Controls movement of molecules into and out of nucleus

STRUCTURE WITHIN NUCLEUS

Inner surface of nuclear envelope lined by nuclear lamina

composed of intermediate filaments

helps organise the packing of DNA within nucleus

DNA ORGANISATION WITHIN NUCLEUS

DNA tightly packed and interacrs with protein called histones

FUNCTIONAL DIFFERENCES BETWEEN EUCHROMATIN AND HETEROCHROMATIN

Euchromatin

- less dense

- contains genes being used by

cell

Heterochromatin

- more dense

- contains genes not being

used by cell

COMPONENTS OF DNA

made up of nucleotides: 5-carbon sugar called deoxyribose, phosphate group, and a nitrogenous base

WATSON-CRICK MODEL OF DNA

DNA has double stranded helical structure

Sugar Phosphate backbone is on outside

Bases on inside

Stabilised by hydrogen bonds

2 polynucleotide strands oriented in opposite directions

GEOMETRY OF DNA MOLECULE

Double Helix Structure

ROLE OF BASE PAIRING MODEL

Adenine [A] = Thymine [T]

Cytosine [C] = Guanine [G]

SEMICONSERVATIVE DNA REPLICATION

each daughter DNA molecule is composed of one original strand and one new strand

MECHANISM OF DNA REPLICATION

To develop technologies

To understand molecular cause of genetic conditions

To create therapeutic proteins

To develop better understanding of relationship between genotype and phenotype

FUNCTION OF MOLECULES REQUIRED IN DNA REPLICATION

Primase = makes RNA primer

DNA Polymerase ||| = synthesises new DNA strand by adding nucleotides complimentary to parental template strand

DNA Polymerase | = Removes RNA primers and fills gap with DNA nucleotides

DNA Ligase = Joins newly synthesised okazaki fragments together

PROTEINS REQUIRED FOR DNA REPLICATION

Primase

DNA Polymerase |||

Helicase

Topoisomerase

Single stranded DNA binding proteins

DNA Polymerase |

DNA Ligase

LEADING AND LAGGING STRAND

Leading Strand = continuously synthesised in 5' - 3' direction

Lagging Strand = discontinously synthesised in 5' - 3' direction as Okazaki fragments

ERRORS IN DNA REPLICATION ARE CORRECTED

1. During Replication (using EXOnuclease)

2. After Replication (using ENDnuclease)

IN VITRO DNA REPLICATION

DNA replication in test tube by Polymerase Chain Reaction

FUNCTIONS OF PCR COMPONENTS

DNA Template

Primers

DNA Polymerase

dNTPs

KARYOTYPE

A display of the chromosome pairs of a cell arranged by size and shape.

PROCESS OF MITOSIS

1. Prophase

2. Prometaphase

3. Metaphase

4. Anaphase

5. Telophase

FUNCTION OF MITOSIS

Produces new cells for growth and repair

2n - 2n

CELL CYCLE

the life cycle of a cell

G1

S1

G2

Mitotic Phase

Cytokinesis

SEXUAL LIFE CYCLE

the production of haploid gametes by meiosis, followed by the union of two gametes in sexual reproduction

STRUCTURES OF MEIOSIS

Interphase (Diploid unreplicated chromosomes)

Meiosis | (Haploid replicated chromosomes)

- Prophase |

- Metaphase |

- Anaphase |

- Telophase |

Meiosis || (Haploid unreplicated chromosomes)

- Prophase ||

- Metaphase ||

- Anaphase ||

- Telophase ||

MITOSIS VS. MEIOSIS

Mitosis:

- Chromosomes align independently

- No chiasmata

- Centromeres on metaphase plate

- Chromatids disjoing

- 2n -> 2n

Meiosis:

- Homologous chromosomes cross over

- Chiasmata

- Chiasmata on metaphase plate

- Chromosomes disjoin

- 2n -> n

SEXUAL REPRODUCTION PRODUCES GENETIC DIVERSITY THROUGH:

Independent assortment of chromosomes

Crossing over

Random fertilisation of gametes

DIVERSITY IMPORTANCE IN EVOLUTION

Variable environments (climate)

Changing environments (seasons)

Sib-Sib competition