Cell Biology Lecture Notes - Chapter 6: A Tour of the Cell

Flashcards covering key vocabulary and concepts from a cell biology lecture.

Microscopy

Tool used to study cells

Robert Hooke

Observed cell walls in 1665

Antoni van Leeuwenhoek

Crafted glass lenses able to visualize living cells

Light microscopy (LM)

Visible light passes through the specimen and then through glass lenses to magnify the specimen.

Magnification

Ratio of an object’s image size to its real size

Resolution

Measure of clarity of image; minimum distance 2 points can still be distinguished as separate

Contrast

Difference in brightness between light and dark areas of an image

Electron microscopy

Focuses a beam of electrons through the specimen or onto its surface

Scanning electron microscope (SEM)

Useful for the study of the topography of a specimen using a beam that scans the surface coated in a thin film of gold.

Transmission electron microscope (TEM)

Used to study the internal structure of cells by aiming an electron beam through a very thin section of the specimen stained with heavy metals.

Cytology

Study of cell structure

Biochemistry

Study of functions/chemical processes (metabolism) of cells.

Cell fractionation

Takes cells apart and separates major organelles and other subcellular organelles from one another.

Centrifuge

Spins test tubes holding mixtures of disrupted cells at a series of increasing speeds.

Prokaryotes

Bacteria and archaea

Eukaryotes

Protists, fungi, animals and plants

Cytosol

Semi-fluid, jelly-like substance where subcellular components are suspended

Nucleoid

Region in prokaryotes where DNA is concentrated and that isn’t membrane bound

Plasma membrane

Separates external environment from internal environment

Nucleus

Contains most of the genes of eukaryotes

Nuclear envelope

Double membrane surrounding nucleus

Nuclear lamina

Protein filaments that maintain nuclear shape

Nuclear pores

Allow proteins and RNA to move in and out of the nucleus

Chromatin

30% DNA, 60% histone proteins, 10% RNA

Nucleoli

rRNA produced here/Sites of ribosome assembly

Ribosomes

Protein factories

Endomembrane system

Membranes within the eukaryotic cell

Vesicle

Sacs made of membrane used for transport

Endomembrane system function.

Metabolism, transportation of proteins, proteins synthesis, movement of lipids and detox of poisons

Endoplasmic reticulum

Endoplasmic reticulum

Extensive system of tubes enclosing fluid-filled cavities (cisternae)

Smooth ER functions

Lipid synthesis (oils, steroids and phospholipids), carbohydrate metabolism, and detox

Rough ER functions

Receives proteins produced by ribosomes/Makes membranes allowing cell to grow or form transport vesicles (makes phospholipids)

Glycoproteins

Secretary proteinsin the ER lumen with carbohydrates bound

Golgi apparatus

Stack of thin membranous sacs and small vesicles

Golgi apparatus role

Traffic director of cellular proteins

•Modify, concentrate, and package proteins and lipids made in RER

•Transport vesicles from RER fuse to cis face of Golgi and shipped on trans face

Lysosomes and vesicles

Vesicles fuses with lysosomes and digestion occurs

Lysosomes

Membranous sac of hydrolytic enzymes

Phagocytosis

Engulf small food particles and bring into cell as vacuoles

Digestion products

Simple sugars, amino acids and other monomers

Autophagy

Degrade worn-out organelles

Vacuoles

Large vesicles derived from ER and Golgi

Food vacuole

Formed by phagocytosis

Contractile vacuoles

In unicellular eukaryotes, pump excess water out of the cell to maintain suitable ion and molecule concentration

Central vacuole

In plant cells, develops by joining of several smaller vacuoles

Mitochondria

Cellular respiration/ATP production site

Chloroplasts

In plants and algae, photosynthesis site

Endosymbiont theory

early ancestor of eukaryotic cells engulfed an oxygen-using non-photosynthetic prokaryotic cell

Mitochondria membranes

Outer is smooth; Inner is folded to form cristae where ATP synthesis occurs

Thylakoids

Flattened interconnected sacs creating membrane system in chloroplast

Granum

Fluid in thylakoids

Stroma

Fluid outside thylakoids that has chloroplast DNA and enzymes

Peroxisomes

Specialized metabolic compartment containing enzymes that remove hydrogen atoms from molecules and transfer them to oxygen to produce H2O2

Glyoxysomes

Found in fat-storing tissues of plant seeds and are used for energy until plant can produce own energy via photosynthesis

Cytoskeleton

Network of fibers extending throughout the cytoplasm

Cell motility

Changes in cell location and movements of cell parts

Microtubules

Hollow rods constructed from tubulin

Centrosome

Region near nucleus where microtubules grow out from

Centrioles

Pair found within the centrosome composed of nine sets of triplet microtubules arranged in ring

Cilia and flagella

Microtubule–containing extensions that project from some cells

Dyneins

Large motor proteins attached along each outer microtubule doublet allow bending

Microfilaments/actin filaments

Thin solid rods built from molecules of globular protein, actin

Plasma membrane

Creates the cortex, a more gel-like substance than liquid-like substance of cytoplasm

Intermediate filaments

Specialized for bearing tension

Cell walls of plants

Extracellular structure of plant cells

Primary cell wall

Young plant secretes thin, flexible cell wall

Middle lamella

Between primary walls of adjacent cells is filled with sticky polysaccharide

Extracellular matrix of animal cells

Glycoproteins and carbohydrate-containing molecules secreted by cells

Plasmodesmata

Channels that connect cells and perforate cell walls

Tight junction

Integral proteins fuse to adjacent cell’s proteins

Desmosome

Anchoring junctions that reduces chances of tissue tearing

Gap junctions

Communicating junction, that directs communication between cells

Cell size

Is limited by cells ability to transport things

Large organisms

Don’t have large cells they juss have more cells

-they have two outer membranes( prokaryotes enguklfed has 2 outer membrames)

-have ribosomes, as well as circular dna

-they are autonomous, can grow or reproduce on their own with in the cell

Endosymbiont theory proof

place where ATP synthesis takes place

cristae