Cell Biology Lecture Notes Flashcards

These flashcards cover cell theory, membrane transport, organelle structure, metabolic processes including photosynthesis and respiration, the cell cycle, and reproduction as detailed in the lecture transcript.

Cell Theory

The theory stating that all living things are made of one or more cells, cells are the basic unit of structure and function in organisms, and cells come from pre-existing cells.

Extracellular fluid (ECF)

The fluid that bathes cells, composed of interstitial fluid and plasma.

Intracellular fluid (ICF)

The fluid found inside cells.

Selectively permeable

A property of the cell membrane that allows it to control what enters and leaves the cell to maintain homeostasis.

Phospholipid

A fat composed of a hydrophilic, polar phosphate head and two hydrophobic, nonpolar fatty acid tails.

Fluid Mosaic Model

A model describing the plasma membrane as a pattern of phospholipids, cholesterol, and proteins that move freely and fluidly in the plane of the membrane.

Glycoprotein

A protein with a carbohydrate attached, found in the cell membrane.

Peripheral proteins

Proteins attached to one end (the periphery) of the cell membrane.

Integral proteins

Proteins that extend across the entire cell membrane.

Aquaporins

Water channel proteins that allow water to diffuse across the membrane fast.

Diffusion

The passive movement of particles from a region of higher concentration to regions of lower concentration until equilibrium is reached.

Osmosis

The diffusion of water through a partially permeable membrane from a less concentrated (dilute) solution to a more concentrated solution.

Hypertonic

A solution with a higher concentration of solutes outside the cell than inside, causing water to move out and the cell to shrink.

Hypotonic

A solution with a lower concentration of solutes outside the cell than inside, causing water to move in and the cell to swell or undergo lysis.

Isotonic

A solution where the concentration of solutes is the same on either side of the cell, resulting in no net movement of particles.

Facilitated Diffusion

The passive diffusion of solutes through transport proteins, such as channel or carrier proteins, down a concentration gradient.

Active Transport

The movement of substances through the membrane against the concentration gradient using energy from $ATP$.

Exocytosis

The process by which a vesicle expels large molecules, such as wastes, to the external environment by tethering to the cellular membrane.

Endocytosis

The process by which a cell takes in large molecules from the external environment by engulfing them and pinching off the membrane to create a vesicle.

Nucleolus

A structure within the nucleus that makes ribosomes and disappears during cell division.

Golgi Body

An organelle consisting of flattened sacs called cisternae that modifies, packages, and helps secrete cell products into vesicles.

Smooth ER

A type of endoplasmic reticulum involved in lipid manufacture, metabolism, production of steroid hormones, and detoxification.

Rough ER

Endoplasmic reticulum with ribosomes attached, involved in protein production, folding, quality control, and despatch.

Mitochondria

The powerhouse of the cell and site of cellular respiration; it contains double membranes with inner folds called cristae and its own $DNA$.

Lysosome

Small organelles containing hydrolytic/digestive enzymes active at acid $pH \text{ (5)}$ for digesting materials.

Chloroplast

The site of photosynthesis in plants and algae, containing chlorophyll and internal systems of sacs called thylakoids stacked into grana.

Cytoskeleton

A network of structural protein fibers ($microtubules, intermediate filaments, and microfilaments$) that gives cells shape and aids organelle movement.

Surface Area to Volume Ratio (SA:V)

A ratio that determines the efficiency of material exchange; cells remain small to maintain a large $SA:V$ for homeostasis.

Metabolic Pathway

A series of chemical reactions where a substrate is converted into a product through several steps involving molecules called intermediates.

Adenosine 5'-triphosphate (ATP)

The principal molecule for storing and transferring energy in cells, composed of adenine, ribose, and $3$ phosphate groups.

ATP Synthase

An enzyme in the mitochondria and chloroplasts that catalyzes the reaction $ADP + P_i \rightarrow ATP$ using a proton ($H^+$) gradient.

Autotrophs

Organisms that produce their own food from inorganic substances using light or chemical energy.

Light-dependent reactions

Photosynthetic reactions occurring in thylakoids that capture light energy to produce $ATP$, $NADPH$, and oxygen.

Calvin Cycle

Light-independent reactions taking place in the stroma that utilize $ATP$ and $NADPH$ to convert carbon dioxide into glucose.

Prokaryotes

Small, simple cells without a nucleus or membrane-bound organelles; $DNA$ is contained in a nucleoid region.

Eukaryotes

Complex cells with a true nucleus and membrane-bound organelles, including plants, animals, fungi, and protists.

Endosymbiotic Theory

A theory suggesting eukaryotes evolved when a large prokaryote engulfed smaller bacteria (like aerobic bacteria or photosynthetic bacteria) that eventually became organelles.

Aerobic Respiration

A process breaking down glucose in the presence of oxygen ($C_6H_{12}O_6 + 6O_2 \rightarrow 6CO_2 + 6H_2O + ATP$).

Glycolysis

The first step of respiration occurring in the cytoplasm where glucose is split into $2$ pyruvate molecules, yielding a net gain of $2$ $ATP$.

Krebs Cycle

The second stage of aerobic respiration in the mitochondrial matrix that breaks down $acetyl coA$ to produce $CO_2$, $H_2O$, $NADH$, and $FADH_2$.

Anaerobic Respiration

Respiration occurring in the absence of oxygen, resulting in alcoholic fermentation in yeast or lactic acid fermentation in animals.

Binary Fission

A fast form of asexual reproduction in prokaryotes where the circular chromosome replicates and the cell divides into two identical offspring.

Haploid (n)

Cells, such as germline cells (sperm/egg), that contain only $23$ chromosomes.

Diploid (2n)

Cells that have $23$ pairs or $46$ chromosomes, found in human body cells.

Chromatin

Loose, uncoiled $DNA$ found in the nucleus when the cell is not dividing.

Mitosis

The cell division process consisting of Prophase, Metaphase, Anaphase, and Telophase that results in two identical daughter cells.

Interphase

The phase of the cell cycle where the cell grows, performs normal metabolic activities, and replicates its $DNA$ in preparation for division.

Cytokinesis

The division of the cytoplasm that follows mitosis or meiosis to form separate new cells.

Metastasis

The process where a tumor disconnects and moves to another location in the body.

Meiosis

A reduction division that results in $4$ genetically unique haploid gametes from one diploid cell.

Crossing Over

The exchange of genetic material between homologous chromosomes during Prophase I of meiosis.

Independent Re-assortment

The random lining up of maternal and paternal chromosome pairs at the equator during Metaphase I, increasing genetic variability.

Natural Selection

The process where organisms better adapted to their environment tend to survive and produce more offspring, driven by genetic variation.

Cell Culture

The process of growing cells in an artificially controlled environment (in vitro) with specific nutrients, hormones, and gases.