2. Organisation of the Organism Flashcards
Where is cytoplasm found and what does it contain?
Cytoplasm is found inside the cell and contains all the other cell structures
What is the nucleus surrounded by and what does this do?
The large nucleus is surrounded by a nuclear membrane to separate it from the cytoplasm
What is the cell wall made of in plant cells and what does it contain?
The cell wall is made of cellulose and surrounds the cell membrane in plant cells
What are chloroplasts, where are they found, description?
Chloroplasts are organelles found in the cytoplasm that are packed with the pigment chlorophyll and so are green in colour
What are vacuoles?
Vacuoles are large vesicles that take up a large part of the interior of plant cells
What organelles are visible in almost all cells when looking at higher magnification?
- mitochondria
- ribosomes
- vesicles
What can ribosomes be found in?
Ribosomes are tiny structures that can be free within the cytoplasm or attached to a system of membranes within the cell known as Endoplasmic Reticulum
Where are vesicles found?
these are small circular structures found moving throughout the cytoplasm
function of the nucleus
- contains genetic material in chromosomes which control how cells grow and work
- controls cell division
cytoplasm function
- supports cell structures
- site of many chemical reactions
- contains water and many solutes
cell membrane function
- holds the cell together
- controls substances entering and leaving the cell
cell wall function
- gives the cell extra support and defines its shape
chloroplasts function
- site of photosynthesis providing food for plants
- chlorophyll pigments absorb light energy needed for the reaction to occur
vacuole function
- contains cell sap
- used for storage of certain materials
- also helps support the shape of the cell
mitochondria function
- site of aerobic respiration providing energy for the cell
- cells with high rates of metabolism (carrying out many different cell reactions) will have significantly higher numbers of mitochondria than cells with lower numbers of reactions taking place in them
ribosomes function
- site of protein production in protein synthesis
vesicles function
- used to safely transport substances from one part of the cell to another
what are specialised cells?
those which have developed certain characteristics in order to perform particular functions.
What are the adaptations of cells controlled by?
These differences are controlled by genes in the nucleus
How do cells specialise? What does it cause?
Cells specialise by undergoing differentiation: this is a process by which cells develop the structure and characteristics needed to be able to carry out their functions
what are examples of specialised cells in animals?
- ciliated cell
- nerve cell
- red blood cell
- sperm cell
- egg cell (ovum)
function of a ciliated cell
movement of mucus in the trachea and bronchi
ciliated cells adaptations
extensions of the cytoplasm at the surface of the cell form hair-like structures called cilia which beat to move mucus and trapped particles up to the throat
nerve cell function
conduction of impulses
nerve cell adaptations
- long so that nerves can run to and from different parts of the body to the central nervous system
- the cell has extensions and branches so that it can commute with other nerve cells muscles and glands
- the axon (extension of cytoplasm away from the cell body) is covered with a fatty sheath which insulates the nerve cell and speeds up the nerve impulses
red blood cell function
transport of oxygen
red blood cell adaptations
- biconcave disc shape increases surface area for more efficient diffusion of oxygen
- contains haemoglobin which joins with oxygen to transport it
- contains no nucleus to increase amount of space available for haemoglobin inside cell
sperm cell function
reproduction
sperm cell adaptations
- the head contains the genetic material for fertilisation in a haploid nucleus (containing half the normal number of chromosomes)
- the acrosome in the head contains digestive enzymes so that a sperm can penetrate an egg
- the mid-piece is packed with mitochondria to release energy needed to swim and fertilise the egg
- the tail enables the sperm to swim
egg cell function
reproduction
egg cell adaptations
- contains a lot of cytoplasm which has nutrients for the growth of the early embryo
- haploid nucleus contains the genetic material for fertilisation
- cell membrane changes after fertilisation by a single sperm so that no more sperm can enter
What are examples of specialised cells in plants?
- root hair cell
- xylem vessel
- palisade mesophyll cell
root hair cell function
absorption of water and mineral ions from soil
root hair cells adaptations
- root hair increases surface area of cell to ensure maximum absorption of water and mineral ions
- walls are thin to ensure water moves through quickly
- no chloroplasts present
xylem vessel function
conduction of water through the plant ; support of the plant
xylem vessel adaptation
- no top and bottom walls between xylem vessels so there is a continuous column of water running through them
- cells are dead without organelles or cytoplasm to allow free passage of water
- their walls become thickened with a substance called lignin which means they are able to help support the plant
palisade mesophyll cell function
photosynthesis
palisade mesophyll cell adaptations
- column shaped to maximise absorption of sunlight and fit as many in a layer under the upper epidermis of the leaf as possible
- contains many chloroplasts for maximum photosynthesis
cells definition
basic functional and structural units in a living organism
tissues definition
group of cells of similar structure working together to perform the same function
organs definition
made from different tissues working together to perform specific functions
organ systems definitions
groups of organs with related functions working together to perform body functions
name 9 different organ systems
- shoot
- root
- digestive
- circulatory
- immune
- respiratory
- excretory
- nervous
- reproductive
shoot system organs
leaf
stem
flower
fruit
shoot system tissue example
- epidermis mesophyll
- xylem
- phloem
root system organs
- root
- tuber
root system tissue example
- xylem
- phloem
- ground tissue
digestive system organs
- oesophagus
- stomach
- small intestine
- large intestine
digestive system tissue example
- muscle
- connective
- nerve
- epithelial
circulatory system organs
- heart
- veins
- arteries
circulatory system tissue example
- muscle
- connective
- nerve
- epithelial
immune system organs
thymus
spleen
immune system tissue example
- bone marrow
respiratory system organs
- trachea
- bronchi
- lungs
respiratory system tissue example
- muscle
- connective
- epithelial
excretory system organs
- liver
- kidney
- skin
- lungs
excretory system tissue example
- muscle
- connective
- nerve
- epithelial
nervous system organs
- brain
- spinal cord
nervous system tissue example
- nerve
reproductive system organs
- ovary
- cervix
- uterus
- vagina
- penis
- testes
reproductive system tissue example
- muscle
- connective
- nervous
- erectile
