This document discusses cells, tissues, and organs. It begins by defining the goals of describing plant and animal cell structures and functions, differences between plant and animal cells, and specialized cell structures. Diagrams of liver and leaf cells show key structures. Plant cells have cell walls and chloroplasts while animal cells do not. Descriptions of red blood, muscle, ciliated, xylem, and root hair cell structures and functions are provided. Tissues are groups of similar cells performing shared functions, while organs are groups of tissues working together. Organ systems are groups of organs coordinating related functions.

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Cells, tissues and organs
AQA Additional Science
Biology B2.1

2. ClickBiology
BTEOTSSSBAT:
• Identify and describe the structure of plant cells and animal cells,
and describe the functions of their parts.
• Describe the difference between animal cells and plant cells.
• Explain the structure and function of specialised cells: red blood cell,
muscle cells, ciliated cells, xylem vessels and root hair cells.
• Define the terms tissue, organ and organ systems, with examples.

3. ClickBiology
BTEOTSSSBAT:
• Identify and describe the structure of plant cells and animal cells,
and describe the functions of their parts.
• Describe the difference between animal cells and plant cells.
• Explain the structure and function of specialised cells: red blood cell,
muscle cells, ciliated cells, xylem vessels and root hair cells.
• Define the terms tissue, organ and organ systems, with examples.

4. ClickBiology
A section through a liver cell (animal cell):
cell membrane
cytoplasm
nucleus
DNA
controls what
enters and
leaves the cell
metabolic
(chemical)
reactions
occur here
contains the
DNA and so
controls the cell
contains the
coded
instructions to
make proteins

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Section through a palisade cell of a leaf
(plant cell)
cell membrane
nucleus
cytoplasm
chloroplast
large sap vacuole
cellulose cell wall

6. ClickBiology
BTEOTSSSBAT:
• Identify and describe the structure of plant cells and animal cells,
and describe the functions of their parts.
• Describe the difference between animal cells and plant cells.
• Explain the structure and function of specialised cells: red blood cell,
muscle cells, ciliated cells, xylem vessels and root hair cells.
• Define the terms tissue, organ and organ systems, with examples.

7. ClickBiology
Comparing animal and plant cells
Found in both animal
and plant cells
Found only in plant
cells
cell membrane cellulose cell wall
nucleus large sap vacuole
cytoplasm chloroplast

8. ClickBiology
BTEOTSSSBAT:
• Identify and describe the structure of plant cells and animal cells,
and describe the functions of their parts.
• Describe the difference between animal cells and plant cells.
• Explain the structure and function of specialised cells: red blood cell,
muscle cells, ciliated cells, xylem vessels and root hair cells.
• Define the terms tissue, organ and organ systems, with examples.

9. ClickBiology
Red blood cells transport oxygen
cell surface membrane cytoplasm contains
no nucleus
cytoplasm contains
haemoglobin
bi-concave disc shape
allows more room for
haemoglobin
increases surface area
over which absorption of
oxygen can occur
haemoglobin is a
protein which carries
the oxygen molecules

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Muscle cells contract and enable movement
of the body
nucleus
cell surface membrane
protein strands
The strands of protein
slide over each other
making the muscle cell
(fibre) shorter and causing
the muscle to contract
Muscle cells have
many nuclei
muscle

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Ciliated cells move bacteria and dust away
from the lungs
cilia
magnification X3000
nucleus
Cilia are small extensions of
the cell. They beat rhythmically
to sweep mucus, which has
trapped bacteria and dust,
away from the lungs

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Xylem vessels transport water and minerals
up the plant
xylem vessel
lignin
no cytoplasm
longitudinal sectioncross-section
water-proof and strong;
helps support the plant
hollow: allows for
continuous flow of water
and dissolved mineral
ions
xylem vessels are continuous tubes

13. ClickBiology
Root hair cells absorb minerals and water
from the soil
cytoplasm
contains no
chloroplasts as no
photosynthesis is
needed
root hair
increases surface area for absorption
of water and mineral ions
Cross-section of a root hair cell
cell membrane semi-permeable, so will
allow water and mineral
ions into the cell

14. ClickBiology
BTEOTSSSBAT:
• Identify and describe the structure of plant cells and animal cells,
and describe the functions of their parts.
• Describe the difference between animal cells and plant cells.
• Explain the structure and function of specialised cells: red blood cell,
muscle cells, ciliated cells, xylem vessels and root hair cells.
• Define the terms tissue, organ and organ systems, with examples.

15. ClickBiology
A tissue is a group of cells of similar
structure that perform a shared function
Animal tissues:
muscle tissue
nervous tissue
upper epidermal
tissue
palisade mesophyll
tissue
spongy mesophyll
tissue
lower epidermal
tissue
Tissues found in the leaf
Cross-section of a leaf

16. ClickBiology
An organ is a structure made of a
group of tissues working together to
perform specific functions
Plant organs include the stem and the leaves
heart
stomach
lungs liver
brain kidneys

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An organ system is a group of organs that
coordinate to perform related functions
In plants the shoot is an organ system consisting of leaves and the stem
lymphatic
system
respiratory
system
digestive
system
excretory
system
reproductive
system
muscular
system
skeletal
system
nervous
system
endocrine
system
circulatory
system

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Levels of organisation
nerve cell nervous
tissue
brain nervous
system
Homo sapiens
smallest largest
cell tissue organ organ
systems
organism

19. ClickBiology
Now you should be able to:
• Identify and describe the structure of plant cells and
animal cells, and describe the functions of their parts.
• Describe the difference between animal cells and plant
cells.
• Explain the structure and function of specialised cells:
red blood cell, muscle cells, ciliated cells, xylem vessels
and root hair cells.
• Define the terms tissue, organ and organ systems, with
examples.

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