1.2 cell structure and organisation

What is the conversion of mm → ųm → nm ?

x1000 → x1000

What is the function of ribosomes ?

The site of protein synthesis (translation)

What is the structure of ribosomes?

Small, non-membrane-bound organelle consisting of two subunits (large/small) made of rRNA and protein

What is the function of the nuclear envelope?

Separates nuclear contents from the cytoplasm, pores control the transport of substances like mRNA and ribosomes.

What is the structure of the nuclear envelope?

Double membrane surrounding the nucleus, with nuclear pores and continuous with the RER

What is the function of the nucleus ?

Stores DNA and controls/codes protein synthesis

What is the structure of the nucleus?

Large, double membraned organelle containing chromatin and the nucleolus

What is the function of the cell membrane ?

controls substances moving in and out of the cell

What is the structure of the cell membrane?

Selectively permeable phospholipid bilayer with embedded proteins and cholesterol

What is the function of the smooth endoplasmic reticulum ?

Synthesizes , stores and processes lipids and hormones

What is the structure of the smooth endoplasmic reticulum?

A network of membrane-bound flattens sacs (cisternae) without ribosomes

what is the function of the flagella/cilia?

Cilia move fluids across the surface and flagella propels entire cells through fluid

What is the structure of the flagella/cilia?

microtomes arranged in a axoneme structure enclosed by a cell membrane

What is the function of the nucleolus?

Makes RNA and ribosomes and sends them to the nucleus

What is the structure of the nucleolus?

Non membrane-bound region inside the nucleus

What is the function of the mitochondria?

Site of aerobic respiration to produce ATP

What is the structure of mitochondria?

Double membranes; inner membrane is folded into cristae, enclosing a fluid matrix contracting 70S ribosomes

What is the function of the centrioles ?

Protein fibres involved in cell division and the production of spindle fibres

What is the structure of the centrioles?

Pairs of hollow, cylindrical structures made of microtubule triplets

What is the function of the Golgi complex?

Modifies, packages and sorts proteins and lipids for transport

What is the structure of the Golgi complex?

A stack of flattened membrane bound sacs with vesicles budding off

What is the function of chloroplasts ?

site of photosynthesis as it converts light energy to chemical energy

What is the structure of the chloroplasts?

a protective envelope, an internal fluid called the stroma, and a network of stacked, flat membrane discs called thylakoids

What is the function of the vacuole ?

Maintains cells rigidity, stores metabolites and isolates waste products

What is the structure of the chloroplasts?

a protective envelope, an internal fluid called the stroma, and a network of stacked, flat membrane discs called thylakoids

What is the function of the cell wall?

Provides mechanical strength, maintains cell shape and prevents plants cells form bursting under osmotic pressure

What is the structure of the cell wall ?

a rigid outer layer surrounding the cell membrane

Where are eukaryotes found and prokaryotes found ?

Eukaryote - animal + plant

Prokaryote - Bacteria / single called organisms

What is the plamodesmata ? What does it allow?

Bridges of cytoplasm between neighbouring plant cells and they allow transfer of substance between cells

What is the size of ribosomes in prokaryotes and eukaryotes ?

Prokaryotes have 70S and eukaryotes have 80S

What are viruses able to do once they invade a cell ?

Takeover the cells metabolism and multiply inside the host cell

What is each virus particle made from ?

A core of nucleic acid surrounded by a protein coat

What are the steps for how something is produced and secreted from a cell? (7)

1. Nucleus

2. Nuclear pore

3. RER

4. Vesicle

5. Golgi body

6. Secretory vesicle

7. Cell membrane

What do multicellular organisms have ? And what do they form?

Specialised cells forming tissues and organs which have various structure and roles

What is a stem cell ?

A undifferentiated cell which can differentiate into any other type of cell

What is a tissue ?

A group of similar cells working together to perform a specific function

What is an organ ?

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

What is an organ system ?

A group of different organs working together working together to perform a specific function

What does a simple cuboidal epithelium tissue look like ? And where is it found?

One layer, cubed shapes found in salivary glands

What does a ciliated columnar epithelial tissue look like ? Where is it found ?

One layer, long column with cilia found in trachea and small intenstine

What does squamous epithelium tissue look like and where is it found?

One layer flattened found in the wall of alveoli

What does the endosymbiotic theory describe? How does it show the formation of mitochondria and chloroplasts ?

Describes the origin of chloroplasts and mitochondria as some cells which were engulfed were good at Turing glucose and oxygen into ATP (mitochondria) and some could turn carbon dioxide and water into glucose (chloroplasts)

What are the 4 types of tissue?

1. Connective

2. Epithelial

3. Nervous

4. Muscle

What are the 3 types of muscle tissue? And how do these act?

• skeletal (voluntary)

• Smooth (involuntary)

• Cardiac (myogenic)

What is skeletal muscle attached to and what does it do ?

Attached to bones and generates movements in mammals (muscles)

Where is smooth muscle found and what does it do ?

Found in the skin + walls of blood vessels and they are involuntary so they contract rhythmically

What is cardiac muscle found and what does it do?

Found in the heart and contracts rhythmically without any stimulation so do not tire

What does connective tissue do? And what does it contain?

Connects, support or separates tissues and organs and contains collagen and elastic fibres

What is the general function of lysosomes?

Contains digestive enzymes which break down organelles

What are the 2 differences between ribosomes in eukaryotic cells and prokaryotic cell?

1. Eukaryotic - 80S ribosomes Prokaryotic - 70S ribosomes

2. Ribosomes are not attached to membranes in prokaryotic