Cell Biology Exam 1

Chloroplasts

Cellulose cell wall

Central vacuole

Plasmodesmata

What do plant cells have that animals don’t?

Robert Hooke

Who coined the term ‘cell’ from looking at cork

Antonie van Leeuwenhoek

Who created the 300x microscope?

Resolution

Seeing two distinct objects under certain magnification:

Cellular fission

Prokaryote replication method:

70S, 3, 55

Prokaryotes have ____ribosomes, ____RNA, ____proteins

80S, 4, 78

Eukaryotes have ____ribosomes, ____RNA, ____proteins

Robert Brown

Who discovered cell nuclei?

Schleiden (plant) and Schwann (animal)

Who formed the Cell Theory?

1. All organisms consist of one or more cells

2. The cell is the basic unit of structure for all organisms

3. All cells arise only from the division of preexisting cells

Cell Theory:

Large size

Ability to ingest nutrients via phagocytosis

Two features developed by protoeukaryotes to distinguish them from other cells:

Aerobic heterotroph

In the endosymbiotic theory, what evolved into the mitochondria

Photosynthetic prokaryote

In the endosymbiotic theory, what evolved into chloroplasts

Adequate surface area/volume ratio

Rate of molecule diffusion

Maintain local concentrations of enzymes and substrates

Three limitations to cell size:

Inwardly fold

What do some cells to do their plasma membrane to maximize surface area?

Inversely

Diffusion is ____ proportional to the size of the molecule

Cytoplasmic streaming/Cyclosis

Actin driven increase in diffusion rate:

Eightfold

How much must reactants and enzymes increase as cells double in size?

Plasma Membrane

Defines boundaries of cell and ensures contents are retained

Phospholipids, other lipids, and proteins

What is the plasma membrane made of?

Two hydrophobic tails

Hydrophilic head

What is a phospholipid made of?

Enzymes

Anchors

Transport proteins

Receptors

Types of proteins on the plasma membrane

Nucleus

Houses DNA-bearing chromosomes of the cell

Nuclear envelope

Encases the nucleus with inner and outer nuclear membranes dotted with nuclear pores:

RNA

What is transported out of the nucleus?

Nucleolus

Region of active synthesis of ribosomal RNA

Interphase

When is DNA formed into less condensed chromatin?

Mitochondrion

Powerhouse of the cell

Accept electrons for the final stage of ATP synthesis

How does the mitochondria require us to breath oxygen?

Circular DNA

Maternal inheritance

Aerobic respiration

Two membranes

What makes mitochondria different from the rest of the cell and similar to prokaryotes?

Chloroplast

Manages photosynthesis in plants

Cyanobacteria

What are chloroplasts structurally similar to?

Inner, outer, thylakoid

Three membranes of chloroplasts:

Thylakoids

Where does light capture via chlorophyll take place?

Stroma

Where does the fixing of carbon dioxide into organics occur?

Nitrogen-ammonia

Sulfur metabolism

What other reactions take place in chloroplasts?

Endoplasmic reticulum

Highway through the cytoplasm of the cell

Cisternae

Flattened stacks surrounding the lumen:

Rough ER

Studded with ribosomes actively making secretory and membrane proteins

Smooth ER

Houses enzymes involved in the synthesis of lipids and steroids, detoxification of toxic compounds

Golgi complex

Stack of flattened vesicles for the processing and packaging of secretory proteins and synthesis of polysaccharides:

Glycosylation

What does the Golgi use to process proteins?

Lysosome

Intracellular digestion, surrounded by a single membrane, developed from late endosomes

Hydrolase

What do lysosomes use to break down biological material?

Peroxisome

Generates and degrades hydrogen peroxide, surrounded by single membrane

Catalase

What enzyme is used to convert hydrogen peroxide into water plus oxygen?

Glyoxysomes

Converts stored fat into carbohydrates for plant germination

Leaf peroxisomes

Helps in photorespiration to hinder photosynthesis

Vacuole

Fluid filled sacs surrounded by a single membrane

Central vacuole

Maintains turgor pressure in plants

Tonoplast

Permeable membrane of central vacuole

Ribosome

Membrane-less organelle for protein synthesis made of large and small subunits

Cytoplasm

Everything inside the cell except the nucleus

Cytosol

Semifluid substance that suspends the organelles

Cytoskeleton

Internal framework of microtubules, microfilaments, and intermediate filaments to give shape and organization

ECM

Collagen fibers with a network of proteoglycans for flexible cellular support

Gap junctions

Intercellular connections specialized for transfer of materials between cytoplasm and adjacent cells

Tight junctions

Hold cells together tightly to block transport of substances between cells

Adhesive junctions

Link adjacent cells into sturdy flexible sheets

Primary wall

Wall laid down during cell division, consisting of cellulose fibrils embedded in polysaccharide matrix

Secondary cell wall

Wall of lignin beneath primary wall that function when dead

Plasmodesmata

Cytoplasmic bridges for cell-cell communication in plants

Pectin lamina

What holds the cells together in plants?

Meristems

Where are newly formed plant cells derived from?

Cellulose microfibrils

500+ glucose residues H-bonded to 60-70 criss cross chains for strength

Orientation of microfibrils

What control the direction of plant growth

Gibberellins

Which plant hormone influence height growth

Ethylene

Which plant hormone influences width growth and is involved in ripening

1. Hormone hits protein

2. Relay molecules

3. Activation of growth

Steps of hormone-triggered growth

Plant growth regulators

Small molecules that penetrate cell walls

Auxin

Keeps axillary buds quiet unless damage, polar transport, cell enlargement, root initiation

Indole Acetic Acid (IAA)

Natural Auxin

Naphthalene Acetic Acid (NAA) and 2,4-D

Types of synthetic auxins

Cytokinins

Hormone derived from adenine involved in cell division

Zeatin and isopentenyl adenine

Natural cytokinins

Benzylaminopurine (BAP) and Kinetin

Synthetic cytokinins

Abscisic acid

Causes senescence of tissues and seed desiccation

Callus

Mass of undifferentiated cells from low or high auxin+cytokinin

Shoots only

Low auxin/high cytokinin

Roots only

High auxin/low cytokinin

Roots and shoots

Intermediate auxin and cytokinin

Selectable marker

Enable the survival of only those cells that have been successfully transformed, effectively eliminating non-transformed cells from the population

Screenable markers

Provide a visual cue to identify transformed cells among a mixed population, allowing researchers to quickly assess transformation efficiency