cell biology

4 functions of cells

metabolism, synthesis of molecules, communication and reproduction

plasma membrane

selectively permeable phospholipid bilayer to protect the cell

proteins permit cells to

attach to other cells or an extracellular matrix

marker molecules

allow cells to identify other cells or other molecules

attachment proteins

allow cells to attach to other cells or to extracellular molecules

channel proteins

form passages for specific ions or molecules to enter or exit the cell membrane

carrier proteins

bind to molecules and change shape to shuttle them across the membrane

atp powered pumps

moves specific ions and molecules across the membrane, requires atp to function.

transport mechanisms

passive transport, active transport, vesicular transport

passive transport

movement of substance from high to low concentration without using atp

active transport

movement of substance from high to low concentration using atp

vesicular transport

uses membrane bound sac called a vesicle, endo/exocytosis, requires ATP

diffusion

movement of molecules from high to low concentration

osmosis

diffusion of water through a selectively permeable membrane

facilitated diffusion

process of diffusion through protein carrier/channels

active transport

substances moved against the concentration gradient, requires atp

secondary active transport

uses a pre existing gradient to transport

endocytosis

movement into the cell

exocytosis

movement out of the cell

phagocytosis

a solid particle is ingested and the vesicle is formed

pintocytosis

dissolves molecules ingested and forms smaller vesicles

cytoplasm

the cell material outside the nucleus but still within the plasma membrane. holds internal structures of the cell

cytosol

the fluid of the cytoplasm

cytoskeleton

gives structure and allows for movement and can deform when the cell divides. made of proteins called microtubles, microfilaments and intermediate filaments

organelles

smaller specialized structures with particular functions

nucleus

membrane bound organelle when genetic information resides

nuclear pores

allow and regulate transport inside and out the nucleus

RNA

a copy of the DNA, can leave the nucleus unlike DNA

nucleolus

structure in the nucleus that manufactures ribosomes

ribosomes

sites of protein synthesis

rough endoplasmic reticulum

creates integral proteins to leave the cell

smooth endoplasmic reticulum

creates lipids to detoxify the body

golgi apparatus

processes and packages proteins and lipids made by the endoplasmic reticulum

lysosome

structure that enables cells to eat and digest unwanted molecules and waste with a special enzyme. formed at the golgi apparatus

autophagy

process of a cell eating itself. happens when a cell is damaged, mutated or the body needs fuel.

peroxisomes

contains a enzyme to break down fatty acids and amino acids. smaller than a lysosome

mitochondria

powerhouse of the cell that creates majority of energy/atp through the krebs cycle

cell cycle

Interphase (G1, S, G2), Mitosis (PMAT), G0 (depending on cell type)

interphase

time spent between division, normal cell activities

G1

routine metabolism and growth

S

synthesis and DNA replication

G2

growth and preparation for division

mitosis

cell division into two identical cells

cytokinesis

division of cell cytoplasm

mitosis phases

prophase, prometaphase, metaphase, anaphase, telophase

prophase

chromatin begins to condense into x shaped chromosomes made of sister chromatids, and the nuclear envelope begins to break down

metaphase

chromosomes align near the center of the cell along the metaphase plate

anaphase

sister chromatids separate and spindle fibers move them to opposite poles of the cell

telophase

chromosomes are pulled to opposite poles, new nuclear envelopes snd cleavage furrow form and chromosomes begin to decondense back into chromatin

cytokinesis

divides the cytoplasm and completes the division of two daughter cells

G0

non dividing states of cell that still carry out its function (eg, neurons)

cancer

result of cell cycle regulation failure, causes creation of tumors

tumors

abnormal mass of tissue, can be benign or malignant

benign tumor

localized, noninvasive and cannot metastasize

malignant

invades surrounding tissue and can metastasize

metastasize

break off and travel to other parts of the body

apoptosis

programmed cell death via autophagy