Cell Biology Concepts

A collection of vocabulary flashcards related to key concepts in cell biology, including organelles, processes, and membrane properties.

Chloroplasts

Organelles that perform photosynthesis in plant cells. ONLY PLANT CELLS HAVE

Cell walls

Structures that provide structural support and shape to plant cells. ONLY IN PLANT CELLS

Large central vacuole

An organelle that stores nutrients and water, crucial for maintaining turgor pressure in plant cells. ONLY PLANT CELLS HAVE

Lysosomes

Organelles in ANIMAL CELLS ONLY that contain enzymes for breaking down waste.

Centrosomes

Structures that contain two centrioles, involved in organizing microtubules during cell division. ANIMAL CELLS ONLY

Endosymbiosis

A theory that explains the origin organelles in modern day eukaryotes, proposing that these organelles were once independent bacteria that formed a symbiotic relationship with ancestral eukaryotic cells. This is an example of endocytosis because the larger cell supposedly folded inward, bonding with and consumed the mitochondria and chloroplasts and they formed vesicles and entered the cells

Transcription

The process of synthesizing RNA from DNA in the nucleus. This occurs in the nucleus of eukaryotic cells and is the first step in gene expression. DNA to RNA: Thymine-Adenine, Adenine-Uracil, Cytosine-Guanine, Guanine-Cytosine

Translation

The process of assembling proteins at the ribosomes in cytoplasm using mRNA as a template. This occurs in the cytoplasm, and is the second step in gene expression.

Fluid mosaic model

The cell membrane is a collage of proteins and other molecules embedded in a phospholipid bilayer. It describes how the membrane's components can move laterally within the layer, contributing to its flexibility and functionality.

Selective permeability

The property of cell membranes that allows some substances to pass through while blocking others.

Passive transport

The movement of substances like SMALL NON POLAR MOLECULES across cell membranes without the use of energy, following concentration gradients. This process includes diffusion, osmosis, and facilitated diffusion.

Active transport

The movement of substances like POLAR MOLECULES, SAME MATERIAL AS FATTY ACID, IONS, LARGE MOLECULES, against their concentration gradient, requiring energy.

Hypertonic

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

Hypotonic

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

Isotonic

A solution with the same concentration of solutes as the fluid inside a cell, resulting in no net movement of water.

simple vs. facilitated diffusion

Simple diffusion is the passive movement of molecules across a membrane without assistance, while facilitated diffusion involves specific transport proteins assisting the movement of larger or polar molecules across the membrane.

integral proteins in the membrane

are proteins that span the entire lipid bilayer, playing key roles in transport and communication across the cell membrane.

peripheral proteins in the membrane

are proteins that are attached to the exterior or interior surfaces of the cell membrane, involved in signaling and maintaining the cell's structure.

cytoskeleton function in membrane

The cytoskeleton provides structural support to the cell, helping to maintain its shape, and plays a crucial role in intracellular transport and cell motility.

extracellular matrix

is a network of proteins and carbohydrates outside the cells that provides structural and biochemical support to surrounding cells, facilitating communication and cell adhesion.

phospholipid bilayer

is a double layer of phospholipids that forms the fundamental structure of cell membranes, providing a barrier that separates the interior of the cell from its external environment. phospholipids: polar hydrophilic phosphate group head and nonpolar hydrophobic fatty acid tails.

cholesterol in membrane

Maintains cell membrane fluidity, stability, and prevents it from becoming rigid or permeable,  it fills in the gaps in between phospholipids,  type of lipid,  more cholesterol less gaps, less things to enter the cell

carbohydrates in the membrane

proteins with covalently attached sugar chains called oligosaccharides,  cell recognition,  immune system,  attached to  the protein:  glycoprotein

endocytosis

process in which materials enter the cell, form of active transport, the material bonds to the outside of the membrane and creates a vesicle then it enters and disconnects from the membrane and can then be utilized or processed by the cell. This allows cells to uptake large molecules and particles.

evidence that the endosymbiosis theory is accurate

First piece of evidence  as to why  organelles evolved this way is because they have their own DNA and the exact same genes as some bacteria,  the insists that they once had their own genetic information and therefore they didnt rely on the genetic information of the larger cell, and  resembling bacterium  also is evidence that they were one separated because bacterium lives on its own. Second Piece of evidence is that chloroplasts and mitochondria are structurally the same as bacteria and they have similar ways of reproduction to bacteria.  the third piece of evidence Is that they have their own ribosomes and two membranes and can make their own proteins and energy.

exocytosis

process in which materials exit the cell, vesicles containing the materials fuse with the plasma membrane, releasing the contents outside the cell. This process is essential for transporting proteins and other molecules out of the cell.

sequence organelles involved in making proteins secreted from a cell

nucleus—rough er—Golgi apparatus—vesicles—plasma membrane

If protein ended up in an organelle instead of secreted what would happen

• Lysosome: it is for breaking down waste so the protein needed to be secreted would be broken down and prevented from carrying out its intended role

• Floated in cytoplasm: if protein reaches cytoplasm before being folded and modified correctly by certain organelles, than it will be misfolded and an inactive protein

example of a cell with specialized function

Muscle cells are specialized for contraction and movement—mitochondria produces energy (ATP) needed for muscle contraction through cellular respiration