1. Cell Structure and function Flashcards
Define Unicellular
A unicellular organism, also known as a single-celled organism, is an organism that consists of a single cell. E.g. a bacteria
Define multicellular
A multicellular organism, is an organism that consists of multiple cells. e.g. a oak tree or a human
What is a cell?
The most basic unit of life that all organisms are made of.
Why are cells called the building blocks of life?
Living things are made up of them ‘ all joined together’
Define ultrastructure
The ultrastructure of a cell is its fine structure as revealed at high magnification.
Define Organelle
Animal, fungal and plant cells all contain structures called organelles. These are specialised for particular functions .
Name 3 structures in an animal cell
Cell membrane, cytoplasm and nucleus
What shape is an animal cell?
It has an irregular structure
What is the function of the cytoplasm?
Site of chemical reactions.
What is the function of the nucleus?
Controls cell activity, contains the genetic material - the DNA
What is the only cell not to have a nucleus?
BACTERIA
(And as an exception the animal red blood cell)
What is the function of the cell membrane?
Controls which substances enter and leave the cell
What is the shape of a plant cell?
It has a regular rectangular shape
What 3 additional structures does a plant cell have compared to an animal cell?
Vacuole, chloroplast and cell wall.
What is the function of the vacuole?
Provides the plant with water and temperature regulation, contains cell sap
What is the function of the cell well?
Provides the plant with structure and support
What is the plant cell wall made of?
Cellulose
What is the function of the chloroplast?
Contains the pigment chlorophyll, where photosynthesis takes place
What is the function of a ribosome? (L5)
Ribosome is the site of protein synthesis
What is the function of a mitochondria?
Mitochondria is the site of aerobic respiration
What is a bacteria? (L5)
Unicellular microorganisms which have cell walls but lack an organised nucleus, including some that can cause disease.
Define flagellum (L5)
flagellum is a microscopic hair-like organelle used by cells and bacteria for movement. (can help them swim in liquid)
Define plasmid (L5)
A plasmid is a small, extrachromosomal DNA molecule within a bacterial cell
Is a fungal cell described more as an animal or plant cell (L5)?
This is a trick question. and the answer can be either depending on how you justify it.
if you say plant cell, you say it is because it has a cell wall.
if you say animal cell it is because it does not have a vacuole or chloroplasts.
Name three parts of a microscope
Any three of the following….
Eyepiece, objective lens, stage, stage clips, mirror, fine focusing dial and course focusing dial.
What part of the microscope reflects light into the eyepiece?
The mirror
What is the job of the objective lens on a microscope?
The help you see the sample by magnifying it. Microscopes commonly include 4x, 10x, 40x, and 100x objective lenses.
Why do we use a stain when preparing a slide.
It allows us to more clearly see the organelles inside a cell.
What stain is useful when viewing plant cells such as in onion tissue?
Iodine solution
What stain is useful when viewing animal cells such as in cheek cells?
Methylene Blue
Define a specialised cell
Cells that perform specific functions are called specialised cells. Each of these cells has special features which allow them to work differently and carry out their intended functions.
Each type of cell has its own job to do. A sperm cell has special features that allow them to perform their functions effectively. List some.
ON order that they can swim to fertilise the female egg they have….
- A tail moves them towards an egg cell.
- Many mitochondria release energy for movement.
- Part of the tip of the head of the sperm, releases enzymes to digest the egg membrane to allow fertilisation to take place.
- The nucleus contains the genetic material for fertilisation.
- Sperm are produced in large numbers to increase the chance of fertilisation.
Nerve cells transmit electrical signals in the nervous system. Describe why they are well suited to their function
- They are thin, and can be more than one metre long in your spinal cord. This means they can carry messages up and down the body over large distances very quickly.
- Nerve cells have branched connections at each end. These join to other nerve cells, allowing them to pass messages around the body.
- They have a fatty (myelin) sheath that surrounds them. The fatty sheath increases the speed at which the message can travel.
Roots hold plants in place as they grow and also absorb water and minerals from the soil. Describe how root hair cells are specialised to maximise the job they do.
Roots divide into smaller and smaller branches as they travel into the soil. The outside surface of roots are covered with root hair cells, which have tiny ‘hairs’ which poke into the soil. This massively increases the surface area for the root hair cell to absorb more water and minerals.
A red blood cell is a specialised animal cell. what special features does it have to help it do it’s job of carrying oxygen around the body.
They contain haemoglobin, which carries oxygen molecules.
They don’t have a nucleus, allowing more space to carry oxygen.
They are a flat disc shape with dips on both sides (biconcave). This gives them a large surface area, and the best chance of absorbing as much oxygen as they can in the lungs.
