A-level Biology 2.1 Cell Structure

Ultrastructure

the detailed structure of a biological entity.

Prokaryotic

An organism whose cells do not have an enclosed organelles, such as bacteria.

Eukaryotic

Cells with membrane-bound organelles

Nucleus

A part of the cell containing DNA and RNA and responsible for growth and reproduction

Nucleolus

The organelle where ribosomes are made, synthesized and partially assembled, located in the nucleus

Rough endoplasmic reticulum

An endomembrane system covered with ribosomes where many proteins for transport are assembled.

Smooth endoplasmic reticulum

Site of lipid synthesis.

Golgi apparatus

A system of membranes that modifies and packages proteins for export by the cell

Ribosomes

Site of protein synthesis

Mitochondria

Enclosed by two membranes with the inner membrane folded; contains its own DNA
Powerhouse of the cell

Lysosomes

cell organelle filled with enzymes needed to break down certain materials in the cell

Chloroplasts

Where photosynthesis occurs; in plant cells only

Centrioles

Structure in an animal cell that helps to organize cell division

Flagella

whiplike tails found in one-celled organisms to aid in movement

Cilia

Hairlike projections that extend from the plasma membrane and are used for locomotion

Organelle

A tiny cell structure that carries out a specific function within the cell

Cytoskeleton

A network of long protein strands in the cytosol that helps support the cell

Transmission electron microscope

an electron microscope that produces two-dimensional images.

Scanning electron microscope

an electron microscope that generates a three-dimensional image.

Differential staining

Using specific stains to distinguish different types of cell

Magnification

The increase of an object's apparent size

Resolution

the shortest distance between two points on a specimen that can still be distinguished by the observer or camera system as separate entities

Eyepiece Graticule

a glass disc fitted into the eyepiece of the microscope. The disc is marked with a fine scale from 0 to 100.

Stage Micrometer

a microscope slide with a finely divided scale marked on the surface. The scale is of a known true length and is used for calibration of optical systems with eyepiece graticule patterns

Vesicles

small membrane sacs that specialize in moving products into, out of, and within a cell

Microfilaments

Long, thin fibers that function in the movement and support of the cell

Microtubules

Thick hollow tubes that make up the cilia, flagella, and spindle fibers.

Intermediate Fibres

Provide mechanical strength and help maintain cell integrity.

Vacuoles

Cell organelle that stores materials such as water, salts, proteins, and carbohydrates

Light Microscope

Basic microscope that uses light and mirrors to magnify small objects.

Counterstain

A stain used to dye unstained cells a contrasting color in a differential stain
Safranin, Safranin, Methylene blue

Artefacts

Things you see down a microscope that isn't part of the cell eg. air bubbles, finger prints, dust

Cytoplasm

A jellylike fluid inside the cell in which the organelles are suspended

Metabolism

All of the chemical reactions that occur within an organism

Histones

protein molecules around which DNA is tightly coiled in chromatin

Chromatin

Clusters of DNA, RNA, and proteins in the nucleus of a cell

Chromosomes

threadlike structures made of DNA molecules that contain the genes

Cristae

series of inner membranes in mitochondria where cell respiration occurs

Matrix

Innermost compartment of the mitochondrion

Mitochondrial (mt)DNA

DNA located in mitochondria