Biology Cell Structure Quiz

Organelles

All cells have those four structures, but eukaryotic cells also have membrane-bound organelles

Organelles = "little organs"

Specialized structures within the cell that work together to help the cell function and survive

Organelles have different functions

Cytoplasm

Structure

Jelly like substance

Mainly made up of water

Function

Holds everything in place

- It is all the empty space / filling

Nucleus

Structure

Contains genetic material (DNA stored as chromatin)

Chromatin looks like spaghetti

Only switches form to chromosomes in the last 10% of its life (during mitosis)

Surrounded by nuclear envelope / membrane with pores that control what goes in and out

Function

Protect the DNA that controls the activities of the cell

Controlling protein production

ONLY RNA CAN LEAVE NUCLEUS, NOT DNA

Nucleolus

Structure

Inside the nucleus

Function

Makes rRNA, which makes up ribosomes

Without nucleolus, no ribosomes => no proteins

Lysosomes

Structure

Contains enzymes

Organic catalyst that speeds up chemical reactions

Functions

Break down dead materials (food, bacteria, old parts of the cell, etc.)

Clean-up system

Vacuoles

Structure

Small and numerous in animal cells

One large central one in plant cells

Function

Storage (water, nutrients, waste, etc.)

Central Vacuole

PLANT CELLS ONLY

Structure

Massive central structure

Function

Storage center (mostly water & nutrients)

Pressure increases rigidity

Folds in on itself

Pressure inside central vacuole goes down => loses rigidity

Cytoskeleton

Structure

Thread-like fibers (Microtubules, Actin filaments, and more)

Made of proteins

Usually not pictured in cell diagrams

Function

Gives cell shape

Ability to move organelles around

Provide structural support for animal cells that don’t have cell walls

Centrioles / Centrasomes

ANIMAL CELLS ONLY

Structure

Made of microtubules

Function

Appear during cell division

Help cell divide by pulling chromosomes apart

Fishing rods connected to chromosomes that reel them apart

Mitosis and miosis

Cilia and Flagella

Structure

Cilia: shorter, more numerous, hair like structures

Flagella: longer and fewer tail-like structures (1-3)

Outside cell surface (both)

Function

Cilia: Move fluid across cell surface

Flagella: Move entire cell

Peroxisome

Structure

Small, free floating in cytoplasm

Function

Breakdown of lipids, detoxification (breakdown of hydrogen peroxide with catalase)

Difference between these and lysosomes, peroxisomes breaks down harmful molecules and lipids, while lysosomes break down ENTIRE organelles

Ribosomes

Structure

Made of proteins and rRNA

Located on rough endoplasmic reticulum (ER) & floating in cytoplasm

Function

MAKE PROTEINS

^ proteins are synthesized right between the large and small sub-unit

Endoplasmic Reticulum

Structure

Internal membrane system

Function

Depends on type: smooth vs. rough

Rough ER

Structure

Has ribosomes on surface

Hugs the nucleus (closest thing to it

Function

MAKES PROTEINS

Smooth ER

Structure

No ribosomes on surface

Attached to outer side of ER

Function

Makes lipids

Golgi Apparatus

Structure

Folded membrane

Function

Gets vesicles (containers) of proteins from ER

Processes, sorts and ships proteins where they are needed

Could be inside or outside of the shell

Postal service - gets proteins where they need to go

^ enters through cisface => travels through apparatus => leaves through transface

Chloroplasts

PLANT CELLS ONLY

Structure

Three parts: Thylakoid, grana (stacks of Thylakoids) and stroma (fluid)

Double membrane (two phospholipid bilayers on top of each other)

Function

Where photosynthesis happens

Converts energy from the sun into sugar (glucose)

Intake light energy => converts into sugar

Autotrophs

Mitochondria

POWERHOUSE OF THE CELL

Structure

Two parts: Inner membrane and matrix (fluid)

Double membrane

Inner membrane has special function

Matrix is the space that the fluid takes up

Function

Where cellular respiration happens

Breaks down food to release energy as ATP (energy currency)

ATP is the physical energy

Mitochondria produces almost all of the energy for a cell and an organism

Cell Wall

PLANTS AND FUNGI ONLY

Structure

Made of cellulose (plants), chitin (fungi)

Function

Protect and maintain shape

^Cell wall is outside of cell membrane

Cell (Plasma) Membrane (Phospholipid Bilayer)

Structure

Surrounds the outside of all cells

Made of two layers of phospholipids

Has embedded proteins

Function

Control what goes in and out of the cell

"Fluid-Mosaic Model" - composed of many parts that move around freely