Academic Biology Unit 2 Test

Williams, Block 3

unicellular

composed of one cell

multicellular

composed of multiple cells that may organize into tissues

organelle

specialized structures within the cell that work together to help the cell function

3 Principles of Cell Theory

1. all living things are made of cells

2. Cells are the most basic unit of life

3. All cells come from other cells

Prokaryote

no nucleus, no membrane bound organelles

Eukaryote

nucleus, membrane bound organelles, multicellular

Things all cells share

1. Genetic material

2. Cell membrane

3. Ribosomes

4. Cytoplasm

Plant cells

chloroplasts, cell wall, and central vacuole

Animal cells

lysosomes, centrioles

Cell membrane

controls what goes in and out of the cell

cytoskeleton

gives the cell its shape and provides structural support for animal cells

cytoplasm

holds everything in place

nucleus

protects the DNA that control the activity of the cell

nucleolus

makes rRNA which makes up ribosomes

ribosomes

make proteins

Rough ER

packages proteins for secretion

Smooth ER

makes lipids (membrane)

Vesicle

mini-carts that transport proteins around the cell

golgi apparatus

processes, sorts, and ships proteins where needed

lysosome

break down dead stuff

vacuole

storage centers for cells

centrioles

help animal cells divide by pulling chromosomes apart

cilia

shorter more hair like projections that move things across the cell’s cytoplasm

flagella

long tail that moves cells whip-like motion thru extracellular fluid

mitochondria

breaks down food to release energy as ATP

chloroplast

where photosynthesis occurs in plant cells

cell wall

provides structure for plant cells

lipids in cell membrane

make up the phospholipid bilayer

phospholipid structure

hydrophilic head, hydrophobic tails

proteins

embedded for transport

carbs

embedded for structure

homeostasis

need of an organism to stay stable by regulating internal conditions

solute

what gets dissolved

solvent

what does the dissolving

solution

uniform mixture of 2 or more substances

concentration

amount of solute dissolved in solvent

positive feedback loop

the output of a system intensifies the response

examples of positive feedback loops

childbirth, fruit ripening

negative feedback loop

the output of a system causes a counter response to return to a set point

examples of negative feedback loops

body temperature, blood sugar

What is the role of the cell membrane in maintaining homeostasis on a cellular level?

The cell membrane is selectively permeable, meaning it controls what goes in and out of the cell.

Simple diffusion

the spreading of molecules across a membrane until equilibrium is reached (O2, CO2, small molecules)

facilitated diffusion

a transport protein helps to facilitate the diffusion of molecules that normally couldn’t pass through the cell membrane. (large, polar molecules)

osmosis

the simple diffusion of WATER across the cell membrane. (hyper, hypo, and isotonic)

molecular pumps

a cell uses energy to pump molecules across the membrane against the concentration gradient (ions)

endocytosis

uses vesicles to move larger particles into the cell (white blood cells)

exocytosis

uses vesicles to transport larger particles out of the cell (neurotransmitters)

hypotonic solution

water concentration outside is higher than the cells cytoplasm, causing the cell to swell

hypertonic solution

water concentration outside is lower than the cells cytoplasm, causing the cell to shrink

isotonic solution

water concentration is the same inside and outside the cells cytoplasm, causing the cell to stay the same.

differentiation

a process that creates special structures and functions

stem cells

undifferentiated cells that become differentiated into one or more types of specialized cells

cell cycle

a repeated pattern of growth, DNA duplication, and cell division that occurs in eukaryotic cells.

chromosome

one long continuous thread of DNA that consists of thousands of genes and regulatory information.

gene

a section of DNA with the instruction for making a protein

sister chromatids

two identical chromatids

centromere

region of condensed chromatid that looks pinched

cancer

uncontrollable cell division

carcinogens

cancer causing agents

What is the order from cell to organism?

Cell, tissue, organ, organ system, organism

What are the two main purposes for cell division?

growth and repair

Interphase

growth phase of the cell cycle, longest part of the cell cycle

What are the three parts of the interphase?

G1 (growth), S (duplication of chromosomes), G2 (more growth and protein synthesis)

Mitosis

the shortest part of the cell cycle, where cell division occurs

prophase

chromosomes form into “x” shapes, the nuclear membrane disappears, and spindle fibers start to appear

metaphase

centrosomes line up in the middle of the cell and connect to spindle fibers

anaphase

sister chromatids separate to opposite sides of the cell

telophase

two nuclear membranes form around the chromosomes, and spindle fibers break down

cytokinesis

the cytoplasm divides into 2 identical sister cells