AQA Biology gcse 1

AQA Biology GCSE Topic 1: Cell Biology Flashcards (Fill in the Blank)

__ cells are eukaryotic.

Animal and plant cells

Animal and plant cells have a __, __, and __.

Cell membrane, cytoplasm, nucleus containing DNA

__ cells are prokaryotic and are much smaller.

Bacterial cells

Bacterial cells have a __, __, __, __ and __.

Cell wall, cell membrane, cytoplasm, single circular strand of DNA and plasmids

Structures in a cell that have different functions are called __.

Organelles

The prefix 'centi' multiplies a unit by __.

0.01

The prefix 'milli' multiplies a unit by __.

0.001

The prefix 'micro' multiplies a unit by __.

0.000,001

The prefix 'nano' multiplies a unit by __.

0.000,000,001

The __ contains DNA coding for a particular protein needed to build new cells.

Nucleus

The nucleus is enclosed in a __.

Nuclear membrane

The __ is the liquid substance in which chemical reactions occur.

Cytoplasm

The cytoplasm contains __ (biological catalysts).

Enzymes

The __ controls what enters and leaves the cell.

Cell membrane

__ is where aerobic respiration reactions occur, providing energy for the cell.

Mitochondria

__ is where protein synthesis occurs.

Ribosomes

Ribosomes are found on a structure called the __.

Rough endoplasmic reticulum

__ is where photosynthesis takes place, providing food for the plant.

Chloroplasts

Chloroplasts contain __ pigment (which makes it green) which harvests the light needed for photosynthesis.

Chlorophyll

The __ contains cell sap and improves cell’s rigidity.

Permanent vacuole

The __ (also present in algal cells) is made from cellulose and provides strength to the cell.

Cell wall

The cell wall in bacterial cells is made of a different compound called __.

Peptidoglycan

As bacterial cells have no nucleus, the __ floats in the cytoplasm.

Single circular strand of DNA

__ are small rings of DNA found in bacterial cells.

Plasmids

__ involves the cell gaining new sub-cellular structures in order for it to be suited to its role.

Cell Specialisation

Cells specialise by undergoing __.

Differentiation

Cells that have the ability to differentiate their whole life are called __.

Stem cells

Sperm cells have a __ to aid swimming.

Streamlined head and long tail

Sperm cells have many __ which supply the energy to allow the cell to move.

Mitochondria

The __ (top of the head of a sperm cell) has digestive enzymes which break down the outer layers of membrane of the egg cell.

Acrosome

The __ is long in nerve cells, enabling the impulses to be carried along long distances.

Axon

Having lots of extensions from the cell body (called __) means branched connections can form with other nerve cells.

Dendrites

The nerve endings have many mitochondria which supply the energy to make special transmitter chemicals called __.

Neurotransmitters

Special proteins ( and ) slide over each other in muscle cells, causing the muscle to contract.

Myosin and actin

Muscle cells can store a chemical called __ that is used in respiration by mitochondria.

Glycogen

__ are specialized to take up water by osmosis and mineral ions by active transport from the soil.

Root hair cells

Root hair cells have a __ due to root hairs, meaning more water can move in.

Large surface area

The __ affects the speed of movement of water from the soil to the cell in root hair cells.

Large permanent vacuole

Root hair cells have __ to provide energy from respiration for the active transport of mineral ions into the root hair cell.

Mitochondria

__ are specialized to transport water and mineral ions up the plant from the roots to the shoots.

Xylem cells

Upon formation of xylem cells, a chemical called __ is deposited which causes the cells to die and become hollow.

Lignin

__ are specialized to carry the products of photosynthesis (food) to all parts of the plants.

Phloem cells

Cell walls of pholem cells form structures called __ when they break down, allowing the movement of substances from cell to cell.

Sieve plates

Despite losing many sub-cellular structures, the energy pholem cells need to be alive is supplied by the __ of the companion cells.

Mitochondria

To become specialised and be suited to its role, stem cells must undergo __ to form specialised cells.

Cell Differentiation

Most specialised cells can make more of the same cell by undergoing __ (the process that involves a cell dividing to produce 2 identical cells).

Mitosis

The first cells of a cork were observed by __ in 1665 using a light microscope.

Robert Hooke

A light microscope has two lenses, an and .

Objective and eyepiece

Light microscopes have, approximately, a maximum magnification of and a resolving power of .

x2000, 200nm

Electron microscopes enable scientists to view deep __.

Inside sub-cellular structures

__ are used to form an image in electron microscopes because they have a much smaller wavelength than that of light waves.

Electrons

There are two types of electron microscopes: a that creates 3D images and a which creates 2D images detailing organelles.

Scanning electron microscope, transmission electron microscope

Electron microscopes have a magnification of up to and resolving power of (SEM) and __ (TEM).

x2,000,000, 10nm, 0.2nm

Magnification of a light microscope: __.

Magnification of the eyepiece lens x magnification of the objective lens

Size of an object = __.

Size of image/magnification

Microorganisms are very small, so in order for scientists to study them they need to grow many of them in the lab using nutrients (__ them).

Culturing

There are two ways to grow microorganisms in the lab: in and on an .

Nutrient broth solution, agar gel plate

Hot sterilised agar jelly is poured into a __.

Sterilised Petri dish

Wire loops called __ are dipped in a solution of the microorganism and spread over the agar evenly.

Inoculating loops

When culturing microorganisms on an agar gel plate, the plate should be stored __.

Upside down

If they have a supply of nutrients and a suitable temperature, bacteria can multiply by __ (one splitting into two) as fast as every 20 minutes.

Binary fission

Number of bacteria at end = __.

Bacteria at beginning x 2number of divisions

To calculate the number of divisions: __.

Divide the time the population is left for by the mean division time for that bacteria

If the bacteria are resistant to the antibiotic they will not die, but non-resistant will die, leaving an __.

Inhibition zone

In both investigations- growing bacteria and testing the effectiveness of antibiotics- you need to calculate cross-sectional areas (of colonies or inhibition zones). This involves using the formula __.

πr²

The nucleus contains your genetic information in the form of __.

Chromosomes

A __ is a short section of DNA that codes for a protein and as a result controls a characteristic.

Gene

There are __ pairs of chromosomes in each cell of the body.

23

__ are the exception to the normal number of chromosomes in a cell: there are half the number of chromosomes.

Sex cells (gametes)

The __ is a series of steps that the cell has to undergo in order to divide.

Cell cycle

__ is a step in the cell cycle- the stage when the cell divides.

Mitosis

Stage 1 of the cell cycle is called __.

Interphase

In mitosis, chromosomes line up at the equator of the cell and __ pull each chromosome of the ‘X’ to either side of the cell.

Cell fibres

Two identical daughter cells form when the cytoplasm and cell membranes divide in a stage called __.

Cytokinesis

Mitosis is also a vital part of __, as this type of reproduction only involves one organism, so to produce offspring it simply replicates its own cells.

Asexual reproduction

A __ is an undifferentiated cell which can undergo division to produce many more similar cells, of which some will differentiate to have different functions.

Stem cell

__ form when an egg and sperm cell fuse to form a zygote.

Embryonic stem cells

__ are stem cells found in root and shoot tips of plants.

Meristems

__ involves an embryo being produced with the same genes as the patient.

Therapeutic cloning

__ is the spreading out of the particles of any substance in solution, or particles of a gas, resulting in a net movement from an area of higher concentration to an area of lower concentration.

Diffusion

Diffusion is __ as no energy is required.

Passive

The movements of gases in the body is called __.

Gas exchange

The greater the __ the faster the rate of diffusion.

Concentration gradient

If the __ is large, the organism is less likely to require specialised exchange surfaces and a transport system because the rate of diffusion is sufficient in supplying and removing the necessary gases.

Surface area to volume ratio

In multicellular organisms the surface area to volume ratio is __ so they cannot rely on diffusion alone.

Small

In the lungs, oxygen is transferred to the blood and carbon dioxide is transferred to the lungs across the surface of millions of air sacs called __.

Alveoli

In the small intestine, cells have projections called __.

Villi

Each gill has plates called __ and upon these are gill lamellae, which is where diffusion of oxygen into the blood and diffusion of carbon dioxide into the water takes place.

Gill filaments

The roots of plants are adapted to take up water and mineral ions via __.

Root hair cells

Carbon dioxide diffuses through __ for photosynthesis, whilst oxygen and water vapour move out through them.

Stomata

The stomata are controlled by __, which change the size of the stomata based on how much water the plant received.

Guard cells

__ is the movement of water from a less concentrated solution to a more concentrated one through a partially permeable membrane.

Osmosis

Osmosis is __ (does not use energy).

Passive

If the concentration of sugar in external solution is the same as the internal, there will be no movement and the solution is said to be __ to the cell.

Isotonic

If the concentration of sugar in external solution is higher than the internal, water moves out, and the solution is said to be __ to the cell.

Hypertonic

If the concentration of sugar in external solution is lower than the internal, water moves in, and the solution is said to be __ to the cell.

Hypotonic

If the external solution is more dilute, water will move into the cell and into the vacuole, causing it to swell, resulting in pressure called __ (essential in keeping the leaves and stems of plants rigid).

Turgor

If the external solution is less dilute, water will move out of the cell and they will become soft. Eventually the cell membrane will move away from the cell wall (called __) and it will die.

Plasmolysis

__ is the movement of particles from an area where they are in lower concentration to an area where they are in higher concentration- against their concentration gradient.

Active transport

Active transport is __ as diffusion is.

Not passive