GCSE - Topic 1 - Cell Biology - Year 9 Flashcards
Cells can be either ____ or ____, fill in the blank.
prokaryotic and eukaryotic
Are animal and plant cells eukaryotic or prokaryotic?
eukaryotic
Which are smaller and simpler, eukaryotic or prokaryotic?
prokaryotic
What are eukaryotes made of?
eukaryotic cells
What is a prokaryote?
a prokaryotic cell (it’s a single-celled organism)
What are the different parts of a cell called?
subcellular structures
What does a nucleus do?
contains genetic material that controls the activities of the cell (eukarotic cells have this, e.g plant and animal)
What does a cytoplasm do?
gel-like substance where most of the chemical reactions happen. it contains enzymes that control these reactions (in plant and animal cells)
What does the cell membrane do?
holds the cell together and controls what goes in and out (in plant and animal cells)
What do the mitochondria do?
these are where most of the reactions for aerobic respiration take place. respiration transfers energy that the cell needs to work (in plant and animal cells)
What do the ribosomes do?
these are where proteins are made in the cell by protein synthesis (in plant and animal cells)
What does the rigid cell wall do?
made of cellulose, it supports the cell and strengthens it (in plant cells)
What do the chloroplasts do?
these are where photosynthesis occurs, which makes food for the plant. they contain a green substance called chlorophyll, which absorbs the light needed for photosynthesis (in plant cells)
What does the permanent vacuole do?
contains cell sap, a weak solution of sugar and salts (in plant cells)
What don’t bacteria cells have that plant cells do?
nucleus, chloroplasts, mitochondria
What do bacteria cells have instead of a nucleus?
they have a single circular strand of DNA that floats freely in the cytoplasm
What is a plasmid?
a plasmid is a small, circular, double-stranded DNA molecule that is distinct from a cell’s chromosomal DNA
Name 4 parts of a bacterial cell.
cytoplasm, cell membrane, cell wall, and the single circular strand of DNA
Name the 5 parts of an animal cell.
nucleus, cytoplasm, cell membrane, mitochondria, and the ribosomes
Name the 8 parts of a plant cell.
permanent vacuole, rigid cell wall, chloroplasts, nucleus, cytoplasm, cell membrane, mitochondria, and the ribosomes
What’s the difference between electron and light microscopes?
light microscopes - use light and lenses to magnify and form a picture or a specimen
electron microscopes - use electrons to form an image, they have much higher magnification and resolution
What is resolution?
the ability to distinguish between two points, so a higher resolution gives a sharper image
Which microscope gives higher resolution and magnification?
electron microscopes
What is the magnification formula triangle?
image size
————— (I AM)
actual size X magnification
What is a slide and what is it used for?
a strip of clear glass or plastic onto which a cell specimen is mounted (rests on the stage of a microscope)
Why are drops of iodine often put onto a slide?
iodine solution is a stain. stains are used to highlight objects in a cell by adding colour to them
What is the larger knob of a microscope called?
the coarse adjustment knob
What is the smaller knob of a microscope called?
the fine adjustment knob
What do you look through on a microscope?
the eyepiece
What is the fine adjustment knob used for?
to adjust the focus and allow you to get a clear image
What is the coarse adjustment knob used for?
to move the stage up and downwards until the image is roughly in focus.
What do you do to get greater magnification?
swap to a higher-powered objective lens and refocus
What is differentiation?
the process by which a cell changes to become specialised for its job
What are the undifferentiated cells called?
stem cells
What is the function of a sperm cell?
to get the male DNA to the female DNA
How is a sperm cell specialised?
- long tail, streamlined head: helps it swim to the egg
- lots of mitochondria in the head to provide energy when needed
- carries lots of enzymes in its head to digest through the egg cell membrane
What is the function of a nerve cell?
to carry electrical signals from one part of the body to another
How is a nerve cell specialised?
- long (to cover more distance)
- have branched connections at their ends to connect to other nerve cells and form a network throughout the body
What is the function of a muscle cell?
to contract quickly
How is a muscle cell specialised?
- long (so they have space to contract)
- contain lots of mitochondria to generate the energy needed for contraction
What is the function of a root hair cell?
to absorb water and minerals
How is a root hair cell specialised?
- on the surface of plant roots
- grow into long ‘hairs’ that stick out into the soil
- gives the plant a larger surface area for absorbing water and mineral ions from the soil
What is the function of phloem and xylem cells?
transporting substances such as food and water around plants
How are phloem and xylem cells specialised?
- phloem and xylem cells form phloem and xylem tubes
- cells are long and joined end to end
- xylem cells are hollow in the centre and phloem cells have very few subcellular structures, so that stuff can flow through them
What is an observation?
people have big feet and spots
What is a hypothesis?
having big feet causes spots
What does repeatable mean?
that if the same person does an experiment again using the SAME methods and equipment, they’ll get similar results
What does reproducible mean?
that if somebody else does the experiment or if a different method or piece of equipment is used, the results will still be similar
What are valid results?
both repeatable and reproducible AND they answer the original question
What is the independent variable?
the variable that you change
What is the dependent variable?
the variable that you measure
What is the control variable?
the variable that you keep the same
What is a control experiment?
an experiment that is kept under the same conditions as the rest of the investigation, but doesn’t have anything done to it
What’s better, a bigger sample or a smaller sample?
a bigger sample
What are the 10 pieces on a light microscope?
eyepiece, arm, stage clips, coarse adjustment knob, fine adjustment knob, high + low power objective lenses, stage, diaphragm, light, and the base
What are the biological drawing tips?
- no shading
- no arrowheads on labels
- straight lines for labels
- non-sketch lines (full lines)
- put a title
- magnification included
How many micrometres is 1mm equal to?
1000
How many nanometres is 1 mm qual to?
1,000,000
What does prokaryotic mean?
before nucleus
What does eukaryotic mean?
true nucleus
