QE 4th

Diffusion

Movement of substances from an area of higher concentration to an area of lower concentration without assistance.

Osmosis

The diffusion of water molecules across a selectively permeable membrane.

Facilitated Transport

Transport of substances across a membrane with the help of transport proteins, typically for hydrophilic molecules and charged ions.

Active Transport

Movement of substances against their concentration gradient, requiring ATP.

Passive Transport

Movement of substances across a membrane without the use of ATP; includes diffusion, osmosis, and facilitated transport.

Hypertonic

A solution with a higher concentration of solutes compared to the cell, causing the cell to lose water and shrink.

Hypotonic

A solution with a lower concentration of solutes compared to the cell, causing the cell to gain water and swell.

Isotonic

A solution with equal concentrations of solutes inside and outside the cell, resulting in no net movement of water.

Endocytosis

The process by which materials are brought into a cell.

Exocytosis

The process by which materials are expelled from a cell.

PHAGOCYTOSIS

Engulfs food or cell

PINOCYTOSIS

Vesicles form around a liquid

RECEPTOR-MEDIATED

Receptors for substances

Enzymes

Organic catalysts made up of proteins that speed up chemical reactions.

Emil Fischer

Creator of the Lock and Key Model in 1894

Substrate

The substance upon which an enzyme acts.

Lock and Key Model

A model that describes the specific interaction between an enzyme and its substrate.

Optimum Temperature

The temperature at which an enzyme is most active, generally between 30⁰C and 40⁰C.

pH Level

A measure of acidity or alkalinity; any change in pH can lead to enzyme inactivity.

Redox Reactions

Chemical reactions involving electron transfer, crucial for biological processes like photosynthesis and cellular respiration.

Oxidation

The process of losing electrons.

Reduction

The process of gaining electrons.

Reducing Agent

A molecule that loses electrons in a redox reaction.

Oxidizing Agent

A molecule that gains electrons in a redox reaction.

Proteases

Enzymes that break down proteins into amino acids.

Carbohydrases

Enzymes that break down carbohydrates into simple sugars.

Lipases

Enzymes that break down fats or lipids into fatty acids and glycerol.

Nucleases

Enzymes that break down nucleic acids into nucleotides.

Factors affecting Enzyme Activity

Temperature, pH levels, and type of substrate are key factors influencing enzyme function.

Activation Energy

The energy required to start a chemical reaction; can be lowered by enzymes.

Meiosis

The process of producing haploid cells from diploid cells through two rounds of division.

Meiosis Pmat of humans

Haploid

A cell that has half the number of chromosomes, denoted as n.

Diploid

A cell that has two complete sets of chromosomes, typically denoted as 2n.

Prophase I

The first stage of meiosis I where homologous chromosomes pair and crossing-over occurs.

Metaphase I

The stage in meiosis I where homologous chromosomes align at the metaphase plate.

Anaphase I

The stage in meiosis I where homologous chromosomes are pulled apart to opposite poles.

Telophase I

The stage in meiosis I where the nuclear envelope reappears around two haploid daughter cells.

Meiosis II

The second round of meiotic division where sister chromatids are separated, leading to four unique haploid cells.

Crossing-over

The exchange of genetic material between homologous chromosomes during prophase I.

Cytokinesis

The final stage of cell division where the cytoplasm divides, resulting in two new daughter cells.

Prophase II

Centrioles doubled and move to opposite ends

Metaphase II

Centrioles release spindle fibers

Anaphase II

Chromosomes are separated from each other

Telophase II

Spindle fibers are gone

Mitosis

The process of cell division where each daughter cell receives a diploid complement of chromosomes identical to its parent cell.

Interphase

The longest phase of the cell cycle where the cell performs its normal functions and prepares for division.

G1 Phase

The first phase of interphase where the cell grows and performs its work with unduplicated chromosomes.

S Phase

The synthesis phase of interphase where DNA replication occurs.

G2 Phase

The third phase of interphase involving final preparations for mitosis, where some conditions may cause the cell to enter G0 or apoptosis.

Prophase

The phase of mitosis characterized by the preparation of chromosomes, the doubling of centrioles, and the disappearance of the nucleolus.

Metaphase

The phase of mitosis where chromosomes align at the metaphase plate and the nucleus disappears.

Anaphase

The shortest phase of mitosis where sister chromatids are separated from each other.

Telophase

The phase of mitosis where chromosomes arrive at opposite poles, decondense, and are surrounded by new nuclear envelopes.

Cytokinesis

The process that occurs after mitosis where the cytoplasm divides, resulting in two daughter cells.

Chromosome

The most condensed structure of a DNA molecule, composed of DNA and proteins.

Gene

A sequence of DNA or RNA that codes for a molecule with a function, acting as a locus on a chromosome.

Diploid

A cell with paired chromosomes; in humans, this includes 46 chromosomes.

Meiosis

A type of cell division that reduces the chromosome number by half, producing gametes.

46

How many chromosomes do humans have?

44

The amount of homologous humans have

2

The amount of nonhomologous (sex chromosomes) in humans

Genome

Prokaryotes & eukaryotes

Checkpoints

G₁ Phase, S Phase, G₂ Phase, and M Phase

RNA

Adenine

Guanine

Cytosine

Uracil

DNA

Adenine

Guanine

Cytosine

Thymine

Mitosis Phase

• Prophase

• Metaphase  

• Anaphase  

• Telophase

Mitosis Pmat of humans