Studied by 38 people
microscope
An instrument that makes small objects look larger
light microscope
sends a beam of light through a cell, which is then focused by two lenses
electron microscope
focuses a beam of electrons through the specimen or onto its surface
Ultrastructure
refers to fine detail, down to the molecular level, revealed by the electron microscope
cytoplasm
A jellylike fluid inside the cell in which the organelles are suspended
nucleus
Control center of the cell, contains DNA
Chromosomes
threadlike structures made of DNA molecules that contain the genes
What contains the instruction for the manufacture of proteins in the cell? What do these proteins determine?
genes, the functions of the cell
HOW does the nucleus determine the structure of the cell and its activities?
The nucleus regulates what proteins are made so it determines the structure and activities
What makes RNA (Ribonucleic acid)
A dark staining part of the nucleus, called the nucleolus
What is the cell membranes function? What is it made out of?
Cell membrane is selectively permeable, made of protein and phospholipids
Chromatin
Clusters of DNA, RNA, and proteins in the nucleus of a cell
Nucleolus
Found inside the nucleus and produces ribosomes
Mitochondria
Powerhouse of the cell- energy supply
Chloroplast
organelle found in cells of plants and some other organisms that captures the energy from sunlight and converts it into chemical energy
cell wall
A rigid layer of nonliving material that surrounds the cells of plants and some other organisms.
Ribosomes
Makes proteins for the cell
prokaryotic cell
A type of cell lacking a membrane-enclosed nucleus and membrane-enclosed organelles; found only in the domains Bacteria and Archaea.
Eukaryotic cells
Contain a nucleus and other organelles that are bound by membranes.
What are cell membranes made out of?
phospholipids and proteins that are in constant motion -membranes are said to be fluid
What is the function of the cell membrane?
The cell membrane regulates what enters and leaves the cell and also protects and supports the cell.
What is the function of the nucleus?
Controls cell activities, stores DNA
What does the nucleus contain?
Contains chromosomes which have DNA (elongated non dividing chromosomes called chromatin)- genetic info.
What does DNA stand for?
deoxyribonucleic acid
Where is the nucleolus located and what is its function?
-Located in the nucleus -makes ribosomes -contains RNA, DNA and proteins
Draw a labelled diagram of the cell membrane
phospholipids, protein, phosphate head, pore, lipid tail, membrane
Draw a labelled diagram of the nucleus
nuclear pore, chromatin, nucleolus, double nuclear membrane, nucleoplasm
Describe the cell wall
made of strong fibrous cellulose (structural polysaccharide)
prevents it from bursting at it fills with water
It is fully permeable and has no control over the entry of substances into the cell.
What does a vacuole consist of?
A vacuole consists of a membrane bag filled with cell sap
Stores sugars and salts that are dissolved in water.
When water moves into the vacuole, it pushes the cytoplasm against the cell membrane and cell wall giving the cell turgor (turgidity)
What happens when water moves into a vacuole?
When water moves into the vacuole, it pushes the cytoplasm against the cell membrane and cell wall giving the cell turgor (turgidity)
Chromatin
Name given to chromosomes when they are elongated and not dividing
What are cell membranes made out of?
Mostly phospholipids and proteins
Why are cell membranes said to be fluid?
Because their components, phospholipids and proteins are in constant motion
What controls the movement of substances in and out of the nucleus?
The nuclear pores on the double membrane of the nucleus
Mitochondria supply energy to the cell in a process know as…
Mitochondria supply energy to the cell in a process know as respiration
Why would some cells need to contain more mitochondria?
Some cells require lots of energy ex. muscle cells
The … of the mitochondria produce energy
The inner foldings of the mitochondria produce energy
The more … a mitochondrion has the more energy it is producing
The more folds a mitochondrion has the more energy it is producing
Draw a diagram of an active mitochondrion and an inactive mitochondrion. State the difference
The active mitochondrion has more folds since it produces more energy in comparison to the inactive mitochondrion
What energy carrier is a source of energy for cells?
ATP
Within a chloroplast, where is chlorophyll contained?
Chlorophyll is contained in thylakoids, in stacks of thylakoids called grana.
What is the difference between grana and thylakoids?
Thylakoids are membrane bound compartments or disks where the light reaction takes place.
Grana are the stacks of these thylakoid disks formed inside the chloroplast.
This is the key difference between grana and thylakoids
Where is the suns energy trapped, and where do light reactions occur?
In the chloroplast - grana - thylakoids
What is the cell wall composed of?
protein , cellulose, polysaccharides
Name 3 differences between an animal and a plant cell
Plant Cell:
Cell wall (shape is rigid)
Large vacuoles
Chloroplasts
Animal Cell
No cell wall (shape can change)
Small vacuoles
No chloroplasts
The structure of a cell seen with the electron microscope is known as the ….
The structure of a cell seen with the electron microscope is known as the ultrastructure
List 4 functions of the cell membrane
retains organelles in the cell
acts as a selectively-permeable barrier
contains receptor sites (for matching molecules such as hormones)
displays antigens (molecules that stimulate the formation of anitbodies
What is the cytosol?
liquid part of the cytoplasm
List 3 functions of the cytoplasm
separates organelles
acts as a storage area for food, salts
chemical reactions occur there
Chromosomes are only visible when they are…
Chromosomes are only visible when they are dividing
What are 3 functions of the nucleus?
controls cell structures and function
DNA replication and nuclear division
controls the formation of mRNA
What is the nuclear membrane?
a double lipo-protein membrane with pores.
retains the nuclear contents
has pores to allow materials in and out of the nucleus
What does RNA stand for?
Ribonucleic acid
What is a ribosome composed of?
proteins and RNA (ribonucleic acid)
What are 2 functions of the cell wall?
(i) to give strength and support to the cell and the whole plant
(ii)to prevent plant cells from bursting when water is taken in by osmosis (It allows the development of turgor.)
Give 3 functions of the vacuole
(i) stores water (this makes the cell turgid)
(ii) stores food (sugar, salt, protein, amino acids, etc.)
(iii) holds gases (02 , CO2)
Cells were discovered by …. in 1665
Cells were discovered by Robert Hooke in 1665
When looking at animal cells under the microscope, describe how you obtained a sample of the cells
Rubbed the inside cheek with a swab
Why is a coverslip used?
to protect the lens
to protect the sample from drying out
Describe how you examined cells using the microscope
Focus using coarse focus
Focus using fine focus
(Marking scheme 3+3)
State the precise location of the cell membrane in plant cells
immediately inside the cell wall
With what type of cell do you associate membrane-bound organelles?
What corresponding term is used to describe bacterial cells?
Eukaryotic
Prokaryotic
The cell membrane is described as being selectively permeable, what does this mean?
Only some substances allowed through
Why is diffusion alternatively known as passive transport?
No (or little) energy (ATP) required
Osmosis is described as a ‘special case of diffusion’ Explain why.
The movement of water or (osmosis) requires a membrane
Name the structure by which Amoeba gets rid of excess water that has entered by osmosis
Contractile vacuole
Give two locations in a cell at which there is a selectively permeable membrane
nucleus, vacuole or chloroplast, mitochondrion
Explain the biological basis for the use of high sugar or high salt concentrations in the preservation of food.
bacteria loses water by osmosis and this causes death
In the human diet zinc, iron and copper are examples of…
In the human diet zinc, iron and copper are examples of trace elements.
The walls of xylem vessels are reinforced with…
lignin
Where in the cell would you expect to find phospholipids?
cell membrane
Vitamin … is an example of a water soluble vitamin.
Vitamin C is an example of a water soluble vitamin.
Name a disorder associated with the deficiency of vitamin D
rickets
What are the final products of digestion of a protein?
amino acids
Note
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