Cell Biology Flashcards
What does cell membrane do?
Holds the cell together, and controls what can and can’t enter the cell
What is cytoplasm?
A jelly-like substance where chemical reactions inside the cell happen. It surrounds all the sub-cellular structures
What is DNA?
Genetic material controlling the activities of the cell
What are ribosomes?
Site of protein synthesis in the cell
What is within an animal cell?
- mitochondria
- cytoplasm
- ribosomes
- nucleus
What extra is in a plant cell?
- cell wall
- chloroplasts
- permanent vacuole
What is the permanent vacuole?
Containing cell Sap which supports the structure of the cell
What is the cell wall?
Made from cellulose + strengthens the cell
What are chloroplasts?
Organelles containing green pigment (chlorophyll) which absorbs light energy for photosynthesis. Contains enzymes needed for photosynthesis
What do bacterial cells never have?
Mitochondria, chloroplasts or a nucleus (they are prokaryotes)
What do bacterial cells have instead of a nucleus?
A circular strand of DNA
What are eukaryotic cells?
Cells with a nucleus (animal and plant cells)
What are prokaryotic cells?
Cells without a nucleus but have genetic material in a single loop of DNA (bacterial cells)
What are bigger , eukaryotic or prokaryotic cells?
Eukaryotic cells
What is a specialised cell?
A cell that has a particular structure and composition of subcellular structures
What is the process that cells specialise through?
Differentiation
What is a cell called that hasn’t differentiated?
An unspecialised cell
How do light microscopes form an image?
They use light and lenses.
It has two lenses (objective lense and eyepiece lense)
What does the objective lense do in a light microscope?
It produces a magnified image and then the eyepiece lense directs the image to the eye
What are microscopes used to see?
Tissues, cells, large sub-cellular structures
What are the two types of microscopes?
Light and electron
What do electron microscopes allow you to do that light microscopes don’t?
View deep inside sub-cellular structures e.g. mitochondria, ribosomes, chloroplasts and plasmids
What are the two types of electron microscope?
- A scanning electron microscope (creates 3D images @ a slightly lower magnification)
- A transmission electron microscope (creates 2D images)
Formula for magnification:
Magnification = image size ➗ real size
Formula for the magnification of a light microscope
Magnification of a light microscope = magnification of the eyepiece lense x magnification of the objective lense
How are sperm cells specialised?
They are specialised for reproduction
-has a long tail and a streamlined head helping it swim to the egg
- lots of mitochondria in cell to provide the energy needed
- carries enzymes in its head to digest through the egg cell membrane
How are nerve cells specialised?
Specialised for RAPID SIGNALLING
function = carry electrical signals from one part of the body to another
- cells are long (cover more distance)
- have branched connections at their ends to connect to other nerve cells + form a network throughout the body
How are muscle cells specialised?
They are specialised for CONTRACTION
Function of a muscle cell = to contract quickly
- cells are long (so that they have space to contract)
- contain lots of mitochondria (to generate energy needed for contraction)
How are root hair cells specialised?
Specialised for absorbing water and minerals
- cells on the surface of plant roots which grow into long ‘hairs’ that stick out into the soil
- gives plant a big surface area for absorbing water + mineral ions from the soil
How are xylem and phloem cells specialised?
Specialised for transporting substances
- the cells form phloem and xylem tubes, which transport substances such as food and water around the plant
- xylem cells are hollow in the centre and phloem cells have very few sub cellular structures so that stuff can flow through them
