Bio Final

Diffusion/simple diffusion

Passive transport; the movement of molecules from areas of high concentration to areas of low concentration (doesn’t require energy)

Osmosis

Diffusion of water across a membrane

Selective permeability

A membrane allows some substances to pass while blocking others - a gatekeeper for the cell

Osmotic pressure

Pressure that develops when water moves across a semipermeable membrane from a region of high to low water concentration.Essential for maintaining cell volume, turgor in plant cells, and overall water balance.

Turgor pressure

Hydrostatic pressure or force exerted by the fluid within a cell againts its cell wall - primarily due to the osmotic flow of water into the cell. Water pressure inside an plant cell. The fluid presses the cell membrane against the cell wall

Plasmolysis

The shrinking of a plant cell’s cytoplasm away from its cell wall - occurs due to the cell losing water in a hypertonic solution. This leads to wilting.

Cytolysis

Swelling of the cell (could cause a cell to explode)

Hypertonic

has a higher concentration of solutes than another solution

Hypotonic

has a lower concentration of solutes than the other solution

Isotonic

Same concentration as the other solution

Phagocytosis

When a cell takes in food by bending around the food and eating it OR when a cell engulfs and digests a solid particle to destroy them or process them for the immune system (type of endocytosis)

Phagocytosis example

White blood cells eating bacteria - immune cells engulf and digest them to protect the body

Pinocytosis

When.a cell takes in fluid that contains nutrients. The fluid particles are engulfed in vacuoles. Another kind of endocytosis

Endocytosis

The process where cells take in material - a type of active transport - three kinds: pinocytosis, phagocytosis, receptor mediated endocytosis

Exocytosis

The process where the cell expels or moves materials out of the cell - active transport/requires energy. Involves vesicles fusing to the membrane to release contents. This process is essential maintaining homeostasis and for releasing substances like hormones and enzymes.

Receptor mediated endocytosis

Needs permission to enter - gets in through receptor - Ex: how cholesterol is absorbed into cells that need cholesterol to build something like a reproductive hormone

Solute

The thing being dissolved

Solvent

The thing doing the dissolving

Concentration

The amount of solute in a given amount of solution

Facilitated diffusion

A type passive transport. Diffusion with the help of proteins like channel or carrier proteins. (move with the gradient, so passive)

Active transport

Cells use energy (ATP) - includes protein pumps, endocytosis and exocytosis

Passive transport

Cells do not use energy - simple diffusion, facilitated diffusion, and osmosis

Crenation

A red blood cell going through plasmolysis due to loss of water in a hypertonic solution, leading to cell shrinkage.

Carrier Proteins

Combine with a substance and help move it across the membrane (without it nerve conduction, which is when nerve impulses are transmitted, would be impossible). (move molecules across gradient so active)

Channel proteins

have a channel that allows a substance to simplt move across a membrane

Cell Recognition proteins

help the body recognize when it is being invaded by pathogens so an immune response can occur

Receptor proteins

Have a shape that allows a specific molecule to bond with it. Causes the protein to change shape and bring a cellular response.

Enzymatic Proteins

Carry out metabolic reactions directly

Junction proteins

form connections between adjacent cells, facilitating communication and structural support.

Hypotonic solution causes the cell to ______

Swell

Isotonic solution causes the cell to _____

remain the same shape

Isotonic, Hypotonic, and Hypertonic solutions all cause ______

osmosis (in isotonic, water flows back and forth in order to maintain equilibrium between the solutions).

Hypertonic solution causes the cell to ________

Shrink

Water always ________

Moves toward the hypertonic solution.

Photosynthesis equation

6CO2 + 6H2O —> C6H12O6 + 6O2

Cell Respiration Formula

C6H12O6 + 6O2 —> 6CO2 + 6H2O + ATP

Purpose of photosynthesis

to convert light energy into chemical energy which is stored in glucose and is used as food

Purpose of cell respiration

To break down glucose and convert it into ATP/usable energy

Role of oxygen in cell respiration

Oxygen acts as the final electron acceptor in the electron transport chain, enabling the production of ATP and water during cellular respiration because it stops a buildup of electrons, allowing the process to continue.

Prophase

The chromatin condenses into visible chromosomes. Each chromosome consists of two sister chromatids joined by a centromere. The nuclear envelope begins to break down, and the mitotic spindle begins to form, with centrioles moving to opposite poles of the cell. Astral rays extend from the centrioles to form the aster, helping in the positioning of the spindle fibers. It is the longest phase

Prometaphase

The nuclear envelope fully dissolves, and spindle fibers attach to the kinetochores, protein complexes found at the centromeres of the chromosomes. The chromosomes begin to move toward the center of the cell

Metaphase

The chromosomes align at the cell’s equatorial plane, called the metaphase plate. Spindle fibers are fully formed, and each chromosome is attached to a spindle fiber from opposite poles via the kinetochores.

Anaphase

The sister chromatids are pulled apart toward opposite poles as the centromeres split. This is driven by the shortening of the spindle fibers. It is the shortest phase. 

Telophase

The chromatids reach the poles and begin to de-condense into chromatin. The nuclear envelope reforms around each set of chromosomes, and the spindle apparatus breaks down

Cytokinesis in animals

It involves the formation of a cleavage furrow. The furrow pinches the cell membrane in the middle, aided by a ring of actin filaments (contractile ring), which tightens until the cell is split into two

Cytokinesis in plants

In plant cells, a cell plate forms in the middle of the cell, which eventually develops into a new cell wall. This occurs because plant cells have rigid cell walls that prevent them from pinching in half. Actin filaments help guide vesicles filled with cell wall materials to the center of the cell, where they fuse to form the cell plate

What are actin filaments

Actin filaments are long, thin protein strands that are part of the cytoskeleton. They play a crucial role in maintaining cell shape, enabling cell movement, and facilitating cellular processes such as cytokinesis.

G1 Phase

The cell grows, and organelles are synthesized. The cell also checks the environment to ensure conditions are suitable for DNA replication.

G2 Phase

 The cell continues to grow and prepares for mitosis. It checks the duplicated chromosomes for errors

S Phase

DNA replication occurs, and the chromosomes are duplicated

M Phase

This phase includes the processes of PMAT (Prophase, Metaphase, Anaphase, Telophase) and cytokinesis. This is the phase of actual cell division.

PMAT (C)

• Prophase: Chromosomes condense, and the spindle apparatus forms.

• Metaphase: Chromosomes align at the cell’s equator.

• Anaphase: Sister chromatids are separated.

• Telophase: Nuclear envelopes reform around separated chromatids.

• Cytokinesis: The cytoplasm divides, forming two daughter cells.
  
  

Cell Division

The process by which a parent cell divides into two daughter cells. It includes mitosis (division of the nucleus) and cytokinesis (division of the cytoplasm).

G1 Checkpoint

Checks for sufficient nutrients, growth signals, and intact DNA to ensure that the cell is ready for S phase

G2 Checkpoint

Ensures DNA has been completely replicated and checks for any DNA damage before moving into mitosis.

M Checkpoint

Verifies that chromosomes are correctly aligned on the metaphase plate and that spindle fibers are attached properly before anaphase can begin

Proto-oncogenes (Cyclins)

Cyclins are proteins that regulate the progression of the cell cycle. In their normal form, they act as “on switches” to promote cell division.

Tumor supressor genes (p53, p27)

 These genes prevent uncontrolled cell division by acting as “off switches.” They detect DNA damage and initiate repair or trigger apoptosis if necessary.

P53

Known as the "guardian of the genome," it halts the cell cycle if there is DNA damage and can initiate apoptosis if the damage is irreparable

P27

It regulates the cell cycle by inhibiting cyclin-dependent kinases, thus preventing the cell from entering the S phase prematurely

Characteristic of cancer cells

Uncontrolled division, insensitive to growth signals, avoid apoptosis, invasion and metastasis, lack of differentiation, abnormal nuclei and shape

Stem cell

A stem cell is a cell that continues to be able to dividend is needed to repair injuries. An example is red bone marrow stem cells which continue to reproduce and become different types of blood cells.

Mutations of what types of genes decrease regulation of the cell cell cycle

Mutations in proto-oncogenes, tumor suppressor genes, cell cycle checkpoint genes

How mutations affect tumor suppressor genes

It causes the cell cycle to become more rapid and decrease apoptosis when it is needed. Leading to more malfunctions and errors within the cell.

What is Binary fission

Binary fission is the division of two daughter cells and it is when the cell separates with a cell wall and plasma membrane. It happens in prokaryotic cells

Transcription

Transcription is the process by which the genetic information in DNA is copied into messenger RNA (mRNA), which then carries the genetic code to the ribosome for protein synthesis.

Translation

is the process by which the mRNA is decoded by ribosomes to synthesize proteins, translating the genetic code into a specific amino acid sequence.

How do transcription and translation relate to the expression of genes

Transcription and translation are two key processes of gene expression, where transcription copies the genetic information from DNA into mRNA, and translation decodes the mRNA to produce proteins, ultimately determining the traits expressed by an organism.