Eukaryotic Cells and their parts Flashcards
What is a eukaryote? (1)
any organism consisting of one or more cells that contain DNA in a membrane bound nucleus
What do eukaryotic cells contain? (1)
many specialized membrane-bound organelles
What is the structure of the nucleus? (4)
it shows darkened patches known as chromatin when stained
surrounded by a nuclear envelope
has nuclear pores to allow molecules to pass through
has a dense spherical structure inside, called the nucleoulus
What is the function of the nucleus?
chromatin consists of DNA and proteins and the instructions for making proteins
chromatin condenses when cells divide into chromosomes
chromosomes are coiled around a number a proteins called histones, this forms complex package
nucleolus makes RNA and ribosomes, which assemble proteins in the cytoplasm
WHat is the structure of the endoplasmic reticulum?
contains flattened membrane bound sacs called cisternae
located on the outside on the nuclear membrane
rough ER is studded with ribosomes
What is the function of the endoplasmic reticulum?
rough ER transports proteins that were made on the attached ribosomes
smooth ER is involved in making lipids and carbohydrate synthesis and storage
What is the structure and function of the Golgi apparatus?
a stack of membrane bound flattened sacs (looks like pita bread)
receives proteins from the ER and modifies them
moves proteins into vesicles that can be transported
What is the structure of mitochondria?
may be spherical or sausage shaped
two membranes : inner membrane is folded to form cristae
the central part of the mitochondrion is called the matrix
What is the function of the mitochondria?
produce adenosine triphosphate (ATP) during respiration
all activities that need energy in the cell is driven by ATP
What are the structure and function of lysosomes?
spherical sacs surrounded by a single membrane
contain powerful digestive enzymes
break down materials, e.g. WBC lysosomes help break down invading pathogens, break down old organelles
What is the function of ribosomes?
site of protein synthesis
act as the assembly line where coded information (mRNA) from the nucleus is used to assemble proteins from amino acids
What is the structure and function of centrioles?
small tubes of proteins fibres (microtubules), there is a pair next to the nucleus in animal cells
centrioles take part in cell division
they form spindle which move chromosomes during nuclear division
What are the darkened patches called when nucleus is stained
chromatin
