diff --git a/GAGE5.py b/GAGE5.py
new file mode 100644
index 0000000..c7dcf77
--- /dev/null
+++ b/GAGE5.py
@@ -0,0 +1,151 @@
+from Bio import SeqIO
+from Bio.SeqUtils import GC
+from abc import ABC, abstractmethod
+
+def filter_fastq(input_path, gc_bounds=(0, 100), length_bounds=(0, float('inf')), quality_threshold=0, output_filename=None):
+    """
+    Filters a FASTQ file based on GC content, sequence length, and quality threshold using Biopython.
+
+    Args:
+    - input_path (str): Path to the input FASTQ file.
+    - gc_bounds (tuple): Tuple specifying the minimum and maximum GC content for filtering. Default is (0, 100).
+    - length_bounds (tuple): Tuple specifying the minimum and maximum sequence length for filtering. Default is (0, infinity).
+    - quality_threshold (float): Minimum quality score for filtering. Default is 0.
+    - output_filename (str): Name of the output file. If None, the default filename will be used.
+
+    Returns:
+    - str: Message indicating the success of the filtering process.
+    """
+    filtered_seqs = []
+
+    with open(input_path, 'r') as fastq_file:
+        for record in SeqIO.parse(fastq_file, 'fastq'):
+            gc_content = GC(record.seq)
+            seq_length = len(record.seq)
+            quality_score = sum(record.letter_annotations["phred_quality"]) / seq_length
+
+            if (gc_bounds[0] <= gc_content <= gc_bounds[1] and
+                length_bounds[0] <= seq_length <= length_bounds[1] and
+                quality_score >= quality_threshold):
+                filtered_seqs.append(record)
+
+    if output_filename is None:
+        output_filename = f"filtered_{input_path}"
+    elif not output_filename.endswith('.fastq'):
+        output_filename += '.fastq'
+
+    with open(output_filename, 'w') as output_file:
+        SeqIO.write(filtered_seqs, output_file, 'fastq')
+
+    return "Filtered data was saved into output file"
+
+
+class BiologicalSequence(ABC):
+    """Abstract base class for biological sequences."""
+
+    def __init__(self, sequence):
+        """Initialize a BiologicalSequence object with a given sequence."""
+        self.sequence = sequence
+
+    def __len__(self):
+        """Return the length of the sequence."""
+        return len(self.sequence)
+
+    def __getitem__(self, index):
+        """Return the item at the specified index."""
+        return self.sequence[index]
+
+    def __str__(self):
+        """Return the string representation of the sequence."""
+        return self.sequence
+
+    @abstractmethod
+    def check_alphabet(self):
+        """Check if the sequence contains valid alphabet characters."""
+        pass
+
+class NucleicAcidSequence(BiologicalSequence):
+    """Abstract base class"""
+
+    DNA_LETTERS = set("ATGCatgc")
+    RNA_LETTERS = set("AUGCaugc")
+    AMINO_ACID_LETTERS = set("ACDEFGHIKLMNPQRSTVWY")
+
+    def check_alphabet(self):
+        """Check if the sequence contains valid nucleic- or aminoacid alphabet characters."""
+        return set(self.sequence).issubset(self.DNA_LETTERS | self.RNA_LETTERS | self.AMINO_ACID_LETTERS)
+
+    def complement(self):
+        """Return the complement sequence."""
+        comp_map_dna = {"A": "T", "G": "C", "T": "A", "C": "G", "a": "t", "t": "a", "g": "c", "c": "g"}
+        return ''.join(comp_map_dna.get(base, base) for base in self.sequence)
+
+    def gc_content(self):
+        """Return the GC content of the sequence."""
+        gc_count = (self.sequence.upper().count('G') + self.sequence.upper().count('C')) / len(self.sequence) * 100
+        return gc_count
+
+class DNASequence(NucleicAcidSequence):
+    """Class representing a DNA sequence."""
+
+    TRANSCRIBE_DICT = {
+        'T': 'U',
+        't': 'u'
+    }
+
+    def __init__(self, sequence):
+        """Initialize a DNASequence object with a given sequence."""
+        super().__init__(sequence)
+        if not self.check_alphabet():
+            raise ValueError("Invalid DNA sequence")
+
+    def transcribe(self):
+        """Transcribe the DNA sequence into an RNA sequence."""
+        transcribed_seq = ''.join(self.TRANSCRIBE_DICT.get(base, base) for base in self.sequence)
+        return transcribed_seq
+
+class RNASequence(NucleicAcidSequence):
+    """Class representing an RNA sequence."""
+
+    def __init__(self, sequence):
+        """Initialize an RNASequence object with a given sequence."""
+        super().__init__(sequence)
+        if not self.check_alphabet():
+            raise ValueError("Invalid RNA sequence")
+
+    def reverse(self):
+        """Return the reverse of the RNA sequence."""
+        return RNASequence(self.sequence[::-1])
+
+class AminoAcidSequence(BiologicalSequence):
+    """Class representing an amino acid sequence."""
+
+    def check_alphabet(self):
+        """Check if the sequence contains valid amino acid alphabet characters."""
+        if not set(self.sequence).issubset(NucleicAcidSequence.AMINO_ACID_LETTERS):
+            raise ValueError("Invalid amino acid sequence")
+
+    def amino_acid_profile(self):
+        """Return the profile of the amino acid sequence."""
+        self.check_alphabet()
+
+        aa_biochemistry = {
+            'hydrophobic': ['G', 'A', 'V', 'L', 'I', 'P', 'F', 'M', 'W'],
+            'polar': ['S', 'T', 'C', 'N', 'Q', 'Y'],
+            '- charged': ['E', 'D'],
+            '+ charged': ['K', 'H', 'R']
+        }
+        profile = {}
+
+        for group in aa_biochemistry:
+            profile[group] = 0.0
+
+        for amino_acid in self.sequence:
+            for group_name, group_list in aa_biochemistry.items():
+                if amino_acid.upper() in group_list:
+                    profile[group_name] += 1
+
+        total_length = len(self.sequence)
+        for group, count in profile.items():
+            profile[group] = round((count / total_length), 2)
+        return profile