Cell Structure and Diversity 5,16

unicellular

an organism consisting of just one cell

multicellular

an organism composed of multiple cells

eukaryotic cells

cells containing a nucleus and membrane-bound organelles

organelles

structures within cells which carry out a particular role

prokaryotic cells

cells that do not contain a nucleus or membrane-bound organelles

nucleoid

the region in a prokaryotic cell where the genetic material is found

cytoplasm

the contents of the cell excluding the nucleus

cytosol

the liquid part of the cytoplasm

animal cells…

do not have a cell wall, do not have chloroplasts, contain small, non-permanent vacuoles

plant cells…

do have a cell wall, do have chloroplasts, contain large permanent vacuoles

magnification of electron microscope

up to 1000000x

cell ultrastructure

the structure of a cell as seen under an electron microscope

2 types of electron microscope

transmission electron microscope (TEM), scanning electron microscope (SEM)

a TEM shows…

the internal structure of a specimen

an SEM shows…

the surface of a specimen

semi-permeable

describes how a membrane allows some small molecules through it

selectively permeable

describes how a cell membrane actively controls the entry and exit of materials in a cell

nucleus

the control centre of the cell, contains DNA wrapped around proteins called histones

Chromatin

consists of DNA wrapped around proteins called histones

chromosomes

condensed, wound up chromatin

Genes

sections of DNA in chromosomes that carry instructions for making proteins

the cell membrane is made up of…

2 layers of phospholipids, known as lipid bilayer

mitochondria

organelles responsible for respiration, the release of energy from food

cristae

folds of mitochondrion’s inner membrane

matrix

gel-like fluid enclosed by inner membrane

ribosomes

the organelles responsible for protein synthesis

endoplasmic reticulum (ER)

organelle responsible for lipid and protein synthesis

rough ER

covered in ribosomes, site of protein synthesis

smooth ER

no ribosomes

cisternae

interconnected tubes making up the ER or membrane-bound sacs making up Golgi apparatus

Golgi apparatus

responsible for packaging protein and lipids manufactured in the ER

cell wall

rigid extracellular layer made of cellulose providing strength and support that prevents cell from bursting

fully permeable

all substances pass through it, e.g cell wall

middle lamella

the space between the cell wall of two cells

chloroplasts

the organelles responsible for photosynthesis; they contain the pigment chlorophyll

vacuoles

membrane‑bound compartments inside a cell that store water, nutrients, and waste materials

turgor

internal pressure exerted by the large vacuole on the cell wall

light microscope magnifications

4x, 10x, 40x

specialised cells

cells that have altered structures to match their specific function

tissue

a group of similar specialised cells carrying out a specific function

organ

a group of different tissues working together to perform a specific function

organ system

multiple organs cooperating to carry out a specific function

stem cells

unspecialised cells in the body

pluripotent

stem cells that can become any type of cell in the body, e.g embryonic

multipotent

stem cells that can develop into a limited number of other cells, e.g haematopoietic cells into blood cells

cloning

artificial copies of stem cells produced in a lab

induced pluripotent

cells that are reverted back to pluripotent cells by scientists

identify organelle

vacuole

identify organelle

cell wall

identify organelle

ribosomes

identify the organelle

Golgi apparatus

identify the organelle

chloroplast

identify the organelle

endoplasmic reticulum

identify the organelle

mitochondria

identify the organelle

nucleus

identify the organelle

cell membrane

identify the cell

plant cell

identify the cell

animal cell