Cell Structure and Function

Cell Theory

all living things are composed of cells, cells are the basic units of structure and function in living things, and new cells are produced from existing cells

Prokaryote

Bacteria, lacking a nucleus

Eukaryote

Plant and animal cells with nuclei and organelles

Organelle

A tiny cell structure that carries out a specific function within the cell

Cytoplasm

the portion of the cell outside the nucleus where organelles are suspended

Nucleus

The organelle that contains the DNA and controls the processes of the cell

Ribosome

site of protein synthesis

Rough Endoplasmic Reticulum

Organelle covered with ribosomes where many proteins for transport are assembled.

Smooth Endoplasmic Reticulum

Makes lipids

Golgi apparatus

Organelle that modifies and packages proteins for storage or release from the cell

Vacuole

Organelle that stores materials such as water, salts, proteins, and carbohydrates

Vesicle

Small membrane-bound sac that functions in moving products into, out of, and within a cell.

Lysosomes

Uses chemicals to break down food and worn out cell parts

Cytoskeleton

A network of fibers that holds the cell together, helps the cell to keep its shape, and aids in movement

Microfilaments

Fine, threadlike proteins found in the cell's cytoskeleton

Microtubules

Tube-like structure in the cell's cytoskeleton

Chloroplasts

Capture energy from sunlight and use it to produce food for the cell

Mitochondria

Convert chemical energy stored in sugars to usable compounds

Cell wall

A rigid structure that surrounds the cell membrane and provides support to the cell

cell membrane

A cell structure that controls which substances can enter or leave the cell.

lipid bilayer

makes up cell membrane, hydrophobic tails and hydrophilic heads

selectively permeable

a property of cell membranes that allows some substances to pass through, while others cannot

the fluid mosaic model

model that describes the arrangement and movement of the molecules that make up a cell membrane

Passive transport

does not require energy

homeostasis

process by which organisms maintain a relatively stable internal environment

diffusion

Movement of molecules from an area of higher concentration to an area of lower concentration.

Facilitated diffusion

Movement of specific molecules across cell membranes through protein channels

Osomosis

Diffusion of water through a selectively permeable membrane

isotonic

the concentration of solutes is the same inside and outside the cell

hypertonic

the solution outside the cell has a higher concentration of solutes

hypotonic

the solution outside the cell has a lower concentration of solutes

cytolysis

cell in hypotonic solution bursts

Active transport

movement against concentration gradient requires energy

Endocytosis

the cell takes in large amounts of material

Exocytosis

Process by which a cell releases large amounts of material

Cell specialization

the process in which cells develop in different ways to perform different tasks

Cell

basic unit of structure in life

tissue

A group of similar cells that perform the same function.

Organ

Groups of tissues that work together to perform a specific function

organ system

group of organs that work together to perform a specific function

Equilibrium

the amount of solute is the same on either side of the membrane

Surface area of a cell

determines the amount of substances that can enter it from the outside environment, and the amount of waste products that can exit to the environment, the cell membrane

Volume of a cell

determines the rate at which materials are used and waste is created

Cell division

Process by which a cell divides into two new daughter cells, cells must divide because SA:V limits their size

Interphase

period of growth and DNA replication in the cell cycle between cell divisions

G1 Phase

stage of interphase in which cell grows and performs its normal functions

S phase

stage of interphase in which DNA replication

G2 phase

stage of interphase in which the cell prepares for mitosis

mitosis

Cell cycle phase in which a single cell divides into two identical daughter cells

cytokinesis

completes the process of cell division

Cyclin

a protein that regulates the cell cycle in eukaryotic cells

Van Leeuwenhoek

First to see organisms under a microscope

Virchow

Proposed that all cells come from other cells

Schleiden

concluded that all plants are made of cells

Schwann

concluded that all animals are made of cells

Aquaporins

channel proteins that facilitate the passage of water