• Wrong document? Swap it for free
  • Written by students who passed
  • Immediately available after payment
  • Read online or as PDF
Sell
Where do you study
Your language
Start selling Create your account
Document preview thumbnail
Preview 3 out of 4 pages
Interview

Cambridge AS Level Biology Notes: Cell structure explained by an A* student

Document preview thumbnail
Preview 3 out of 4 pages

Cambridge AS level notes for unit 1 Cell Structure. I achieved an A* for the Cambridge AS and A-Level Biology examination and an A* for the Cambridge GCSE Biology examination. I have summarized all the important points and included diagrams to aid understanding.

Content preview

ANIMAL AND PLANT CELLS
ANIMAL CELL PLANT CELL
Surrounded by a cell surface membrane
SIMILARITIES Contains the nucleolus within the nucleus
Contains many organelles (e.g.: mitochondria)
Contains a nucleus
Contains cytoplasm
No cell walls Contains cell walls
DIFFERENCES No large permanent vacuole Contains a large central vacuole
No chloroplasts Contains chloroplasts




Chromatin – Loosely coiled form of chromosomes that is made up of DNA and proteins

Nucleolus – A densely stained body found inside the nucleus

It manufactures ribosomes using information in its own DNA

Organelle – A functionally and structurally distinct part of a cell

VIRUSES
Features:

• No cell structures
• Not surrounded by a cell membrane containing cytoplasm
with ribosomes
• Contains a protective coat of protein molecules (capsomere)
• Contains a self-replicating molecule of DNA or RNA
• Size: 20 – 300 nm
• They are parasitic
• Reproduce by infecting and taking over living cells

, PROKAROTIC AND EUKARYOTIC CELLS
PROKARYOTES EUKARYOTES




Diameter: 0.5 – 5 micro meters Diameter: 40 micro meters
Circular DNA No circular DNA
DNA lies freely in the cytoplasm DNA contained in nucleus
Naked DNA DNA is associated with proteins to make chromosomes
Small 70s ribosomes Larger 80s ribosomes
No Endoplasmic Reticulum Contains Endoplasmic Reticulum (sometimes with
ribosomes)
Cell wall present Cell wall sometimes present (plants and fungi)
(made up of murein, a peptidoglycan)
Very few organelles Many organelles

• No membrane: ribosomes, centrioles, microtubule
• Single membrane: lysosomes, Golgi body, vacuole
• Double membrane: nucleus, mitochondrion,
chloroplast
Bacteria Animals, plants, fungi, protoctists
COMMON STRUCTURES IN PROKARYOTES AND BACTERIA
• Cell wall
• Cell surface membrane
• Cytoplasm
• Circular DNA
• Ribosomes

ADDITIONAL STRUCTURES IN BACTERIA AND THEIR FUNCTONS
• Flagellum - Locomotion
• Capsule - Protection
• Plasmid – Small circle of DNA
• Pili – For attachment to other cells/ surfaces, for sexual reproduction
• Cell membrane infoldings – For nitrogen fixation

, ORGANELLES
organelle structure function
Nucleus • Surrounded by 2 membranes called the • Nuclear pores control the
nuclear envelope exchange between the
nucleus and the cytoplasm
• Nuclear envelope has small nuclear • Substances leaving the
pores nucleus:
• mRNA, ribosomes
• It contains chromosomes in the form of • Substances entering the
chromatin nucleus:
• Chromosomes contain DNA • Proteins
• DNA is organized into genes • Genes control cell activities
and inheritance
• Nucleolus makes ribosome
Ribosomes • Has 2 subunits: large and small • Protein synthesis
• Made up of RNA and protein
Endoplasmic Reticulum • Membranes form an extended system
of flattened compartments called sacs • Smooth ER makes lipids an
• Its continuous with the outer steroids (cholesterol,
membrane of the nuclear envelope oestrogen, testosterone)
• Rough ER: covered with ribosomes • Rough ER synthesizes
• Smooth ER: not covered with proteins
ribosomes
Golgi body • A stack of flattened sacks • Collects, processes and
• Made when vesicles break off from the sorts molecules for
ER transport in Golgi vesicles
either to other parts of the
cell or out of the cell.
• Makes glycoproteins
• Removes the 1st amino acid
methionine
• Makes lysosomes

Lysosomes • Spherical sacs • Digests old organelles or
• Surrounded by a single membrane whole cells
• No internal structure • In WBC, lysosomes are use
• Diameter: 0.1 – 0.5 micrometers to digest bacteria
• Contain digestive enzymes
Mitochondria • Diameter: 1 micrometer • Aerobic respiration (produc
ATP)
• Sausage shaped
• Lipid synthesis
• Double membrane bound
• Inner membrane is highly
• Inner membrane is folded to form
selective and controls what
cristae
ions and molecules can
• Matrix: interior solution
enter the membrane
• Intermembrane space is the space
between the 2 membranes
• Outer membrane has a transport
protein called porin
• Replicate independently of cell division
by dividing into 2

Connected book
 image
Publisher: 2016 ISBN: 9781107589476 Edition: Unknown

Document information

School year
200
Uploaded on
June 4, 2021
Number of pages
4
Written in
2020/2021
Type
Interview
Company
Unknown
Person
Unknown
£3.10

Wrong document? Swap it for free Within 14 days of purchase and before downloading, you can choose a different document. You can simply spend the amount again.
Written by students who passed
Immediately available after payment
Read online or as PDF

Sold
0
Followers
0
Items
6
Last sold
-




Why students choose Stuvia

Created by fellow students, verified by reviews

Quality you can trust: written by students who passed their exams and reviewed by others who've used these revision notes.

Didn't get what you expected? Choose another document

No problem! You can straightaway pick a different document that better suits what you're after.

Pay as you like, start learning straight away

No subscription, no commitments. Pay the way you're used to via credit card and download your PDF document instantly.

Student with book image

“Bought, downloaded, and smashed it. It really can be that simple.”

Alisha Student

Working on your references?

Create accurate citations in APA, MLA and Harvard with our free citation generator.

Working on your references?

Frequently asked questions