BIOL 5 lecture 3B

Cellular Transport

Cellular Transport

Process of moving substances within the cell and moving substances into and out of the cell.

Passive and Active transport

Types of Cellular Transport

Diffusion

The passive transport of particle from an area of high concentration to an area of low concentration.

Facilitated diffusion

Uses transport proteins to move ions and other small molecules across the plasma membrane.

Osmosis

The diffusion of water across a membrane.

Isotonic Solution

Those in which concentrations are equal on each side of the membrane.

Hypotonic solutions (Swelling)

Those in which the concentration of solutes outside the cell is lower than the concentration inside the cell.

Hypertonic Solutions (Shrinking)

Those in which the concentration of solutes outside is higher than the inside.

Active transport

Happens when a substance moved against a concentration gradient, from a low concentration to a higher concentration.

Endocytosis

A process by which a cell surrounds a substance in the outside environment.

Exocytosis

The secretion of materials at the plasma membrane.

Pinocytosis and Phagocytosis

2 types of endocytosis

Pinocytosis

Takes in fluids and solute. Cell drinking

Phagocytosis

Takes in larger substances. Cell eating

Photosynthesis

The process by which plants capture energy from the sun to build carbohydrates through chemical pathways.

6CO2 + 6H2O → C6H12O6 + 6O2

Chemical formula for photosynthesis

Light-dependent reactions

• Takes place in membranes

• These reactions’ goal is to convert light energy to chemical energy in the form of ATP (Adenosine triphosphate) and NADPH (Nicotinamide adenine dinucleotide phosphate).

Light-Independent Reaction

• Also known Calvin cycle

• The second phase of photosynthesis that does not required a light.

• Occurs in the stroma of the chloroplast

• The Calvin uses the ATP and NADPH that were produced during the light-dependent reaction.

Produce sugar

Goal of Calvin cycle using ATP and NADPH

Carbon fixation

A carbon dioxide molecule combines with a five-carbon acceptor molecule, ribulose biphosphate (RuBP). This step makes a six-carbon compound that splits into two molecule of a three-carbon compound, phosphoglyceric acid (PGA).

Reduction

2nd stage of Calvin cycle.

ATP and NADPH are used to convert the PGA molecules into molecules of a three-carbon sugar, phosphoglyceraldehyde (PGAL).

Regeneration

Some PGAL molecules go to make glucose, while others must be recycled to regenerate the RuBP acceptor. Regeneration requires ATP and involves a complex network of reactions.

Cellular Respiration

The process by which mitochondria break down food molecules to produce ATP in plants and animals.

The goal of this process is to change organic chemical energy (glucose) into inorganic chemical energy (ATP).

Considered as the reverse of photosynthesis.

Aerobic and Anaerobic respiration

Types of cellular respiration

Glycolysis, Citric acid or Krebs Cycle, and the Electron transport chain.

Three stages in cellular respiration.

Glycolysis, Pyruvate Oxidation, Citric acid cycle, and Oxidative phosphorylation.

4 stages of cellular respiration

Glycolysis

A six carbon sugar undergoes a series of chemical transformation in the cytoplasm. And in the end, it gets converted into two molecules of pyruvate, a three-carbon organic molecule. In these reaction, ATP is made, and NAD+ is converted to NADPH.

Pyruvate oxidation

A process where a two-caron molecule bound to Coenzyme A, known as acetyl CoA. Carbon dioxide is released and NADPH is generated.

Citric Acid Cycle

The acetyl CoA made in the last step combines with a four -carbon molecule and goes through a cycle of reactions, ultimately regenerating the four -carbon starting molecule. ATP, NADH and FADH2 are produced, and carbon dioxide is released.

Oxidative phosphorylation

The NADH and FADH2 made in other steps deposit their electrons in the electron transport chain, turning back into their "empty" forms (NAD+ and FAD). As electrons move down the chain, energy is released and therefore ATP is produced.

Cell cycle

A process of a cell from the time it is formed until it is capable to divide and make new cells.

Interphase

The cell grows, replicates irs chromosomes, copies organelles, and prepares for cell division.

G1, S, and G2 phase

In order for a cell to move from the interphase into the mitotic phase, it has to undergo three specific stages,

G1 phase

The cell grows physically larger and copies the organelles inside the cell. S

S phase

or the synthesis phase

Let the cell amke complete copies of the DNA in its nucleus.

G2

the cell grows more, makes proteins and organelles, and prepares the cells for the M phase.

Mitotic Phase

The M phase

Mitosis

Division of somatic or body cells into two new cells

Cytokinesis

Division of cytoplasm

Prophase

• Chromatin condenses into chromosomes

• Nucleus disappears

• Spindle fibers form

• Nuclear envelop breaks down

• Spindle fiber attaches to chromosomes

Metaphase

Chromosomes line up along metaphase plate

Each chromosome should be attached to microtubules from the opposite ends of centrosomes

Anaphase

Sister chromatids separate

Spindle fibers pull the chromatids towards the poles

Telophase

Spindle fibers disintegrate

Nuclear envelops form around both groups of chromosomes

Chromosomes convert their extended form (chromatids) again.

Meiosis

• Division of reproductive or sex cells (ex. sperm and egg) in eukaryotic organisms

• It has two cell divisions forming four unique daughter cell

Prophase I

• Starting cell is diploid

• Homologous chromosomes pair up and exchange fragments

Metaphase I

Homologue pairs line up at the metaphase plate

Anaphase I

• Homologues separate to opposite ends of the cell

• Sister chromatids stay together

Telophase I

• Each chromosomes has two (non-identical) sister chromatids

Prophase II

• Starting cells are the haploid cells made in meiosis I

• Chromosomes condense

Metaphase II

• Chromosomes line up at metaphase plate

Anaphase II

• Sister chromatids separate to opposite ends of the cell

Telophase II

• Newly forming gametes are haploid

• Each chromosomes has just one chromatid