Biology Unit One Cells Study Guide

Cell Theory

Cell Theory

The principles stating that all living things are made of cells or cell products, the cell is the smallest unit of life, and cells arise from existing cells.

Exceptions to the Cell Theory

Examples that challenge the cell theory, such as striated cells with multiple nuclei, giant algae that are large in size, and aseptate fungal hyphae with multiple nuclei.

Functions of Life

The processes that living organisms must perform, including metabolism, response, homeostasis, excretion, nutrition, growth, and reproduction.

Surface Area to Volume Ratio

The ratio of the cell's surface area to its volume, which is important in limiting cell size because smaller cells are more efficient in terms of metabolism.

Magnification and Actual Size of Electron Micrographs

a.     Magnification – measure scale bar, convert to appropriate unit, calculate magnification by  division of converted scale bar over scale bar value

b.    Actual size – measure object/image, convert to appropriate unit, calculate actual size by image s/w unit over magnification

Cell Specialization

The process by which newly formed cells deactivate certain genes to specialize in specific functions or roles.

Types of Stem Cells

Different categories of stem cells, including totipotent (able to differentiate into any cell type), pluripotent (able to differentiate into many cell types), multipotent (able to differentiate into a few closely related cell types), and unipotent (able to regenerate only their own cell type).

Current Uses of Stem Cells

The applications of stem cells in research and medicine, which include studying cell development, testing new drugs, and potentially treating diseases and injuries.

Prokaryotic Cells

Cells that lack a nucleus and membrane-bound organelles, have DNA located in the cytoplasm, contain a single circular chromosome, and divide by binary fission.

Eukaryotic Cells

Cells that have a nucleus and membrane-bound organelles, have DNA associated with proteins, contain multiple linear chromosomes, and divide by meiosis or mitosis.

Organelles

Structures within cells that have specific functions, such as the nucleus, mitochondria, endoplasmic reticulum, Golgi apparatus, and lysosomes.

Cell Membrane

The structure that surrounds the cell and regulates the movement of substances in and out of the cell, composed of a phospholipid bilayer with embedded proteins.

Types of Proteins Associated with the Cell Membrane

Integral proteins, which are permanently embedded in the cell membrane; peripheral proteins, which have a temporary association with the cell membrane; and glycoproteins, which are proteins with sugar or carbohydrate chains attached to them.

diffusion

The net movement of particles from an area of high concentration to an area of low concentration.

Facilitated Diffusion

The passive diffusion of substances from an area of high concentration to an area of low concentration using transport proteins.

osmosis

The diffusion of water across a membrane, from an area of lower solute concentration to an area of higher solute concentration.

active trabsport

The net movement of substances across a membrane against their concentration gradient, requiring energy input from the cell.